USGS topo map questions

[caveman]

I've exhausted most of my local trees for the tree i.d. and after reading through the disorders thread, I have some more of those we can look at, but I thought it might be fun to look at some maps.  I suspect a lot of you relied on these to do your jobs, especially before GPS.

 
 
1.  What is the contour interval on this map?
2.  What is the elevation of C.?
3.  What is the combined acreage of the two black hash marked tracts?
4.  Which vegetation type is at C.?
5.  Which feature is SE of Ford's Arm

This map show up better for me on my computer in my gallery.  It is under State Forestry.

[beenthere]

Can't tell anything from the pic. 
All that info should be in the borders of the map, iirc. 

Do you know the answers to your questions and just seeing if we can give the answers that you know? 

[caveman]

There should be enough info on the parts of the map pictured to answer.  I will try to post a picture of the rest of the map.  It is the Lake Jackson Quadrangle map (Florida).

The area outlined with the red marker in the top picture is section 36.  It has one black hash marked area with the black marker.  I tried to put a picture of the whole map, but the glare and resolution was too bad.  I left the map at work and won't be back there until Thursday.  

[Old Greenhorn]

1: 10'
2: 220'
3: no idea
4: forested
5:  swamp

Never learned computing acreage from a topo. Need a lesson.

[caveman]

Tom, you were right on 1, 4, and 5.  A section is 640 acres.  There are 36 sections in one township.  A section is also one square mile.  Each side of a section is one mile, 5280 feet, or 80 chains.  This will be useful information in the following days.  

[beenthere]

Caveman
It is, until it isn't. Not all sections are created equal, so may lead to a trick question. 

[Dan_Shade]

I'm guessing, is the answer to the second question 205ft?

[Old Greenhorn]

Nah, it's 210'. I fat fingered when I typed in my answer.

[Dan_Shade]

If it's 210, why doesn't it touch the 210 line near it?

I'm either dense or confused... 

[Southside]

Honestly I was surprised to see contour lines on a topo map of Florida.  :D

[Ianab]

Honestly I was surprised to see contour lines on a topo map of Florida.  :D

At ~250ft, it's probably called Mount "something"  :D

[caveman]

I'm not trying to trick anyone.  The best I can tell is that that (C.) is at 200'.  Notice that it is on an index line, which are darker and bold.  With a contour interval of 10', those will always fall on multiples of 10 and 50.  I generally try to get to an elevation spot from two index lines to confirm that I'm selecting the right elevation.  

There is a place on peninsular Florida that is about 310' above sea level.  It is the site of Bok Tower, which was designed by Fredrick Law Olmstead.  He's the same guy who designed Central Park in NY.  The site of Bok Tower is called Iron Mountain, and it is on the Lake Wales Ridge.  It was a great citrus growing site prior to Citrus Greening.  

Southside, most of the maps around my place have contour intervals of 5'.  I lived at an address on the map used above from age 3 until 7.  I had some really good strawberries on my knees from crashing bicycles and skateboards on the newly paved subdivision roads there.  Then we moved to where we live now and with the dirt roads, the skateboarding ended.  I still found ways to get hurt.   

[Old Greenhorn]

AH OK, I mis-understood the question. I pegged 210' where that dot is.
I too was interested to see that interval. I rarely work with a map that has less than a 20' interval around here. In fact, you often sees 6 to 10 of those lines right on top of each other. One of my 'challenge short hikes' I used when training for long backpacking trips was a 1,200' gain in one mile of trail. As I was training I would increase my load while trying to decrease my time, ending up using a 60 pound pack for the climb. I always thought I was doing good for and old guy (I was around 50 at the time) until one day I passed a grandma in her 70's coming down while I was sucking wind going up. I chatted with her for a minute, turns out she does that trail about 4 times a month and has done it for decades.... in house slippers. >:(
My goal had always been to do that trail in the depth of winter when the snow is very heavy and the rest is solid ice. Full crampons, ice axe, etc. 3 times I tried, 3 times I failed halfway up. One time was really not pretty and I sliced up my gaiter one one leg with my crampons from the other foot. If I had got the leg, I might have been in for a rough time. All I'll say is it is not pleasant hurtling back down the hill on your back, head first with your feet point uphill and you can't get your axe into anything because of your speed and the density of the ice.
But I digress, sorry.
Back decades ago I was working as a bike mechanic at the paraolympics (long story) and there was a team of riders from FL that I got friendly with. I asked about their training and where they find hills to work with. He joked and said the highest point in the 5 county area is the landfill at 250'. :D They train for hills on the bridges, which can often exceed 200' ASL and they do them over and over.

[caveman]

Back in 1989 we bicycled across a good bit of Alaska, and we trained for it in Florida. Our longest day was 136 miles, but we also climbed Thompson's Pass, which was around 10,000'.  The only fond memory I have of that day is going downhill for 17 miles heading toward Valdez.  That trip nearly cured me from riding a bike.  

[SwampDonkey]

Never really used topo maps here unless locating road placement. Scale was 1:20,000 on any we had access to. Pretty much used dot grid on aerial photography for areas, 1:12500 scale (all aerial photography in NB forestry). Timber cruising sample locations all off aerials. Other than that, silviculture boundaries were all measured by compass and string box. Then GPS and GIS took over. Had access to property paper maps and microfiche for property size for at least 40 years. Aerial photography been around since the 50's and updated 3-10 years apart generally, but mills often did their own annually. I remember new photos over blocks cut a few months before. Cut blocks were measured post harvest here off aerials, was close enough. Only time I seen measuring string in the woods was for plantation post treatment and thinning pre-treatment. In BC the cut blocks were traversed pre harvest with turn points (falling carners) marked on trees, nylon chain (distance), compass (direction) and clino (for slope changes).

[caveman]

The answers to yesterday's were:
1.  10' contour interval
2.  200' elevation of C.
3.  160 acres combined in the two sections
4.  Forest is green on the map
5.  Swamp or Marsh (there are several types of swamp or marshes)



 
6.  What is the feature that the D arrow is pointing to?

7.  South of the boxed in area, a blue line with three blue dots and more blue lines is seen.   There is another to the west of the boxed in area in the next section over.  What is that feature?

[Texas Ranger]

A marsh and intermediate streams.  I had a problem with the original question when I blew it up to see, it became blurry, old eyes, ya'know.

[clearcut]

The National Wetlands Inventory believes 

D =  This 18.90 acre Freshwater Forested/Shrub Wetland habitat is classified as a PFO6F.

Classification code: PFO6F
System Palustrine (P) : The Palustrine System includes all nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses or lichens, and all such wetlands that occur in tidal areas where salinity due to ocean-derived salts is below 0.5 ppt. It also includes wetlands lacking such vegetation, but with all of the following four characteristics: (1) area less than 8 ha (20 acres); (2) active wave-formed or bedrock shoreline features lacking; (3) water depth in the deepest part of basin less than 2.5 m (8.2 ft) at low water; and (4) salinity due to ocean-derived salts less than 0.5 ppt.
Class Forested (FO) : Characterized by woody vegetation that is 6 m tall or taller.
Subclass Deciduous (6) : A plant community where deciduous trees or shrubs represent more than 50% of the areal coverage of trees and shrubs. The canopy is normally leafless some time during the year.
Water Regime Semipermanently Flooded (F) : Surface water persists throughout the growing season in most years. When surface water is absent, the water table is usually at or very near the land surface.

The blue dot dash symbol representes an intermittent stream. 

The National Map allows you to create a topo, or other maps for anywhere in the US.

[WV Sawmiller]

   Neat topic and visuals. Most of the maps I used were military maps and were typically 50,000:1 IIRC.


  I used to have a drawer full of Camp LeJeune maps I got from the G-2 section and used to have to give map reading classes to fuzzy headed guys in rubber boots with funky BO because when we did a
 big field exercise I'd have to order the Porta-Johns for the exercise. Jacksonville/Onslow County NC area had a high water table and with limited training area we could not dig catholes or slit trenches on that scale so we (I) had to rent porta johns. I'd order 50-100 to be dropped at a 6 digit grid coordinate at a major dirt road intersection or such and we'd move them with tactical MHE and camo them up to hide them so they did not give away the camp from the air. The delivery/service guys could not read a map and did not know the grid system (and had a pretty regular turnover of employees) on one so I'd have to give classes to them every time we'd order them.

  We'd have designated admin times for the service trucks to come pump them and we'd provide a guide to escort the guy to where we had them placed/hidden then we'd have to rake out the tracks so the camp would be hidden from the air.

  I still have nightmares about Porta-Johns. On a big multi-service exercise not long before I got out the pumper truck died and the toilet were full and the medical gurus were threatening to shut down the exercise so the CG was chewing on my boss (the HQ Bn CO) and he was chewing on me. I told him the guy was a civilian and I could not shoot or court martial him and all I could do per the contract was refuse payment. The guy was trying and knew he would get the next award too as nobody else had the numbers we needed.

  BTW - you know the Soil Service people can provide Aerial Photos of your property which are also great tools. I had one of my place and when my son was a teenager he roosted some turkeys while bow hunting and we had an on-going Fall season and he was able to show me exactly which tree they were in and I got up the next morning and went up there and filled one as off the roost as soon as it got daylight.  

[peakbagger]

One of the many potential casualties of the Reagan Revolution was nearly all USGS maps. On the hit list to get rid of was the government wasting money printing all sorts of specialty maps including USGS quads. The concept was the government would still develop the database but if someone wanted a map they would have to buy it from private industry. Many folks depended on the USGS maps so a compromise was agree upon. Much of the rural areas of the US were still working on the series of 15 minute maps developed in the 1920s as they were the most recent. I was out bushwhacking mountains along the Canadian border in Maine and the most recent maps In the mid 1980s were dated 1921 showing roads and logging camps long gone. The compromise was that the USGS would stay in the map business until all the 7.5 minute quads were created and printed. That took a long time, well after Reagan retired and most forget about the deal. During this period, the government initially developed indexes of what the maps would be named and their catalog code long before the map actually existed and even when it was created and printed, their inventory records were not up to date. For a couple of years I would go in the index of future maps that were not supposed to exist and order them anyhow direct from the USGS and about 90% of the time they would ship me one. These were and still are labeled as provisional so they still have cartographer field notes but the topo was based on satellite data.  The other thing I learned from someone on the early internet was that anyone buying $500 worth of USGS maps was considered a dealer and got the maps for half price. Me and another person ended up buying two orders at half price and I still have that map collection. 

The papermill I worked for in NH was one of the suppliers of the map paper, it was high grade acid free paper designed to be folded and unfolded and printed with very stable ink. They still can get trashed if soaked for an extended period, but the ink does not run and usually if carefully unfolded and dried they are still legible. For a while various map dealers went to custom printed maps instead of keeping the USGS maps, they looked good when new but most were printed with lower grade paper and with an ink jet type ink. They rapidly broke down when wet and the ink would fade. 

It is pretty amazing the accuracy standards that were put in place for USGS maps considering most were made before Lidar.. Here are some details on the accuracy standards Map Accuracy Standards (usgs.gov)

I still tend to hike "old school" using maps and terrain features rather than the "follow the beep" GPS approach. There are hiking "lists" of high points that many people attempt to complete. The more obscure lists are to summits without trails. Pre GPS everyone ended up taking a slightly different route spreading out the use until the various routes converged near the top over the paths of least resistance. Now that GPS is so popular, folks either download tracks by folks who have done it previously or follow a route on a ap like Gaia. The result is the majority of the use is contrained to narrow track which quickly becomes a beaten down track. It has taken a lot of the challenge out of climbing those peaks. If folks lose their GPS devices or they stop working they usually get lost as in these rural areas, there may not be cell service. Some folks pay a subscription fee for devices that talk to satelites so they can text home and tell their spouse to call 911 and send the rescue team. There have even been cases where folks are lost and do have cell service and know their location but do not have a map so Fish and Game has to send a crew out to lead them out of the woods.  

[Old Greenhorn]

Interesting detail there Peak. Thanks for that. I too tend to rely on my map, a real map, not some digital thing. I have bought some topo's that lasted one day on the trails and flaked out when they got wet. Ticked me off because they still charged top dollar. I fold my maps for the days trip, so they get re-folded a lot. My habit was to buy two of each quad, one for the house and route planning, and one for my pack and use on the trail.
 I do love my maps and have a few on the wall that I refer to from time to time to figure things out. But they've been up there nearly 40 years now.

[caveman]

I appreciate the participation and education.  
6.  Was a submerged wooded swamp
7.  Intermittent stream (wet weather stream)  

TexasRanger, the map gets blurry when I blow it up also.  I had a lot of these maps laminated so that I could write on them with markers and erase my marks to reuse.  I've made several tests on some of these maps.  At one time, I was trying to teach my students with only one topo map.  

Later in the week I'll try to get some better map pictures and post a few more questions.  Others feel free to jump in and just add questions.  

[SwampDonkey]

What I used to go find at DNR was the cover type maps for areas I never hunted much on. They'd show me the roads, even the old grown in ones that I liked best, that were on clear cut hardwood forest. Those places always had grouse a plenty, fill your bag limit for that day. I always hunted on foot. Some people just drive all day on main logging roads and hardly see a bird.

[Texas Ranger]

Back when I was flying bugs I developed a folding map like we used in the service and could put a counties topo in my lap for flight and bug recording.  Basically, a four-color road map in grids that also showed woods.  Put them on a cloth and wax backing and a heat applied cover plastic that we could use over and over.  I think we used the same maps for years.

[SwampDonkey]

We laminated aerial photos here for the woodlot owner groups. Photos were always signed out for use in the woods. They might end up behind a pickup seat for a few weeks before coming back.........if the dog didn't it. :D  Anyway, we could mark them with grease pencil or marker for cruising and drawing in boundaries for sampling. Just rub off with a good white erasure. We used photos for ten years before the new updates came in. All the paper maps in the office where orthophotos. But not updated since 1983 or so, only the photos got updates. But those maps had property boundaries which never changed much. The photos were treated like a map, had scale and could draw the boundary on it from the orthophoto map. Not much for mountains here. I never saw a hill that couldn't be cut. Sometimes it depended on the approach, but it could be cut. :D

[YellowHammer]

I used the old paper topo maps for finding secret fishing spots on our lakes and the Gulf of Mexico.  Old homesteads, ponds, humps, especially submerged roads were all gold.  I pored over them for hours, finding potential hotspots.  

Now, for bodies of water, everything is digital and updated almost daily.  In the marine world, the detail is often to 1 foot resolution, in 3D, and if the option is "turned on", every depth finder in the world with the capability, is linked via Skynet and anytime I drive over a spot, the new depths and details are uploaded (I have less than 1" target resolution on my units) and after so many units have uploaded data, the number are crunched by computer, maps are automatically updated and then automatically broadcast back to out to all the units, corrected for tide and water level.  All hands off, just takes a credit card to get the subscription service.  This is especially useful when dealing with shifting sandbars, fish aggregating devices, and obstructions.  Amazing technology.

[SwampDonkey]

For what I do, I only need basic stuff. Lengths, and area and a polygon. A weeks collecting is worth more than the GPS. :D All I get is a paper map with all the topo features and the boundary of the area to go measure on the ground. We use a fire grid system, so it is easy to locate any block to rough in a GIS boundary on computer to transfer to the GPS. My GPS has all the forestry roads, creeks, names and properties that you don't get when you buy a GPS. Get those from a government site and make my own custom map layers, which aren't GPX files. I can put aerials on the GPS, but I don't need them for anything. I'd use aerial photos on the GPS perhaps if cruising, otherwise nothing gained.

[caveman]

I used the old paper topo maps for finding secret fishing spots on our lakes and the Gulf of Mexico.  Old homesteads, ponds, humps, especially submerged roads were all gold.  I pored over them for hours, finding potential hotspots.  

Evidently one of our renters took my marine charts from our place at Anna Maria.  I had charts that I had been marking since I was a teenager.  I spent hours looking at those charts looking for spots like you are referring to.

[Southside]

Took me a second to figure out what you were saying there YH.  In my mind all I was thinking was why would there be topo lines ON the lake or the ocean.  :D

[caveman]

Back before I had a Loran or a GPS on the boat, we would leave from a known point, like the lighthouse on the point of Egmont Key and take a particular azimuth.  JMoore wore a watch and I'd watch the water pressure operated speedometer on the dash.  He would calculate how far we had been and let me know when we should be at our target destination.  We would set down and look at the bottom with a sonar flasher.  It is amazing that we ever caught any good fish or found the charted spots we were looking for.  

Now fishing is more like a video game, so I've been told.  It has been a while since I harassed the grouper or snapper.  

[YellowHammer]

It's just like a paper map, just more accurate and easy to visualize.  Here's the bottom geography of the Northern Gulf of Mexico, from the beach to the Desoto Canyon, which is the edge of the continental shelf.  Yellow is shallower, blue is deeper, the edge of the canyon is from 300 to 1,000 feet.  

 

 
 

  

[Old Greenhorn]

This is an interesting thread and I am enjoying reading along. Caveman made me think of one of the most unusual navigation techniques I have ever known of either on land or sea. Now I have learned both land and water navigation over 6 decades, was good at both for a fair part of my life, but have forgotten most of the finer points and details.
 We used to fish every year on the St. Lawrence Seaway, nest Clayton. Sitting in the boat everyday I got to watch a lot of lakers and other large vessels go by, even had to get out of the way of a few. Over the years I started reading and studying a bit about them and got some books written by local pilots and such. 
 When they make it through the locks, those Lakers pick up a river pilot who guides the ship through the river out to Lake Ontario, where he/she gets off and catches a ride back to do it again, or pilots a down bound ship out. Those pilots have their own marked up charts. They navigate by speed and time. They use a stop watch to time their progress at a given speed from landmark to landmark and the time to begin their turns as well as how many degrees they alter their course. (Those lakers turn slowly, so one needs to 'plan a turn'.)
 The seaway is a very difficult place to navigate a large ship. The depth can range from a few hundred feet, to just 39' or so (which is only a few few deeper than the ship's draft). In the shallow sections, if a ship moves too fast it can create a suction effect between the bottom of the hull and the bottom of the channel and suck the ship right down, grounding it. They also have to consider the water speed which is working against them up bound and pushing them faster down bound. The up bound and down bound speed limits are different for vessels over a certain length and draft. If I recall it was 5 MPH up bound and 7 MPH down bound, but these change each year based on river conditions and levels which can very a lot year to year.
 Also, some sections are only wide enough to barely allow passage of the wider ships. Navigation must be extremely precise. If a fog comes in the seaway can become extremely hazardous for these ships. One year we got socked in for a day and a night and when the fog lifted we saw ship and lakers in the oddest areas. They had managed to find some natural deep water outside of the seaway channel and anchor up, blowing fog horns from time to time and lighting their decks.

[Ianab]

Maps have always been fascinating to me too. I do like the newer digital versions, and the ability to locate yourself on them. A paper map is fine if you already know where you are, if you don't then it can be a challenge to get yourself orientated. If you have the local topo map saved on your phone, push the button and "You are here" appears, and it will tell you which way is North. As long as the map is saved, you don't need internet, the GPS and saved map data are there. 

This is the online topo map for NZ, centred on the farm I grew up on. I think it's only 15m (~50ft) gradations.  So it's not like Florida  :D

New Zealand Topographic Map - NZ Topo Map

But you can scroll around. zoom in and out over the whole country. 

[SwampDonkey]

Today's forest cover type maps are all online now. They say it's only for crown land, but it includes private lands as well. Shows boundaries, areas, perimeter and estimated standing timber volume in cubic meters/ha. I checked one stand on my property from their map. They have the volume pretty low, it's 2 to 3 x more wood than their estimate. I've actually cut off as much as their per ha estimate and there's a lot more wood than that especially back where the fir out number and out grow the spruce. :D

[Machinebuilder]

I love maps. I hate the movement away from paper maps.
I like having a big paper map spread out so i can see everything in between 2 places.

I also like my GPS, it can tell me where I am and I can usually find it on the map.

one App I have on my phone is Avenza, with it you can download USGS quads, including historical ones and MVUM for the forest service roads.
They are Georeferenced PDF's so the GPS shows where you are on the map.

On the USGS site you can get download the USGS Quads and historical ones. NO COST.

I used to play a photo tag game and one spot was a steam engine in the mountains. I got rather lost.
The latest map data (GPS and paper) came from 1963 USGS quads, since then several roads had been rerouted and closed.
I got stopped at a locked gate in a farmers pasture, looking at the road i wanted to be on.

I find it interesting to look at the historical maps, With the TVA lakes there are drastic changes before and after the dams closed

[Texas Ranger]

I got lost in Arkansas once using car gps, it kept wanting me to take gated roads through pastures.  I then used dead reconning and headed in general direction I wanted to go while the gps kept telling to take u-turns.  Got there. 

[SwampDonkey]

GPS maps preloaded I don't trust. They have roads were there never was one unless it was from the 50 or 60's or something. No sign of certain mystery roads or even plowed up berms. They don't have many forest roads on them, big gaps in data. The forestry stuff I get, at least exist, some aldered or flooded. I usually trace back from a work block to the main haul road because sometimes there are two ways in, but one not maintained. Used to sign forestry roads, but the signs are long gone.

[caveman]

 


8.  What are the double dashed lines on the map seen in section 36?
9.  What direction is the intermittent stream in section 36, just above T3n on the right side of the map flowing?
10.  What section number is the partial section shown below section 36?
11.  What is the highest elevation shown on the section asked about in question #10?
12.  What part of Florida is this quadrangle located, north, central or south?

[Ron Scott]

I have a number of nautical maps of the Great Lakes from the 1960's when I was actively shipwreck and underwater log hunting. We then started using them with the Loran when the Loran was developed. Some of my maps that have shipwreck locations on them have now become collectors' items and framed as large wall displays in lakeside bars and homes.

[caveman]

8.  What are the double dashed lines on the map seen in section 36?
9.  What direction is the intermittent stream in section 36, just above T3n on the right side of the map flowing?
10.  What section number is the partial section shown below section 36?
11.  What is the highest elevation shown on the section asked about in question #10?
12.  What part of Florida is this quadrangle located, north, central or south?

Furby is pretty good at the map questions, fellows.
Answers: 8.  Unimproved road (dirt road)
              9.  northwest, towards the lake.  The contour lines point to the source of the water.
              10.  section #1
              11.  178'
              12.  north Florida  The STR system in Florida is based off of the Prime Meridian Marker, which is located on the grounds of the old Capital, in Tallahassee.  Everything with a Township line denoted N, is north of that spot, Ranges denoted E, are east of that spot.
I did not bring any maps home, so I'll have to see if any of the pics in my gallery are clear enough to use for questions.

[SwampDonkey]

Your maps use pretty much the same symbology as ours. Our older maps will even show location of camps, farming community buildings or maybe hamlets with square dots for buildings. We have miles and miles of rural roads with buildings dotted along. They have started to put those symbols digitally on maps in the last couple years, for all buildings.

Locally, the army goes on orienteering and survey exercises on rural roads around here. I always see them carry paper maps.

[caveman]

 

Assume that the square B is in is the same size as the other three.  Write a legal land description for B (You will not be able to include township and range due to the poor resolution of the other pictures of this map).
13.  Legal land description of B
14.  How many acres is B?

[Ljohnsaw]

• 14 - 40 acres

[caveman]

Again, I apologize for the quality of the pics.  What I came up with is the nw 1/4 of the se 1/4 of the nw 1/4 of section 4 and it is 10 acres.  

[Ljohnsaw]

Hmm, guess I didn't look close enough. I thought it was 1/16 of a section, not 1/64. I see it now.

[caveman]

Generally, sections are divided, using this system into 1/2's and 1/4's.  A 1/4 is 160 acres, a 1/4 of a 1/4 is 40 acres, 1/4 of 1/4 of a 1/4 is 10 acres and a 1/4 of a 1/4 of a 1/4 of a 1/4 is 2 1/2 acres.  Any 1/4 will be ne, se, sw, nw, while any half will be n, s, e, or w.

At the bottom of these USGS maps is symbol that gives the magnetic declination from true north.  The declination varies depending where in the world you are.  I cannot make it out on the map pictured below, but let's assume it is 2 1/2° W.  

Question #15.  If the map shows 180° for us as an azimuth for us to follow to go from one point to another, what azimuth on our compass should we follow to not miss our mark?


  The magnetic declination information is right above the pink, photo revised information.  I can't read either on this picture.  A few other informative things can be found along the bottom of the map include revisions, scale, contour interval, location relative to the state, road types and the date the map was first made.

[Ljohnsaw]

Well, it's going to be one of the other. Never done this before. If you're saying it is 2.5°W, I would think that means you need to rotate counter clockwise that amount, so add?  Heading would be 182.5°.  Otherwise it should be 177.5°. eh, what's 5° off on a heading?😜

[clearcut]

This is a trick question.  Magnetic Declination changes over time.  According to NOAA's Magnetic Declination Calculator   the current magnetic declination for the area near Lake Jackson, FL is 5°9' W and changing Westerly at plus or minus 21' per year. 

As this is a Westerly variation, one subtracts the declination from the bearing. 180- 5= 175° should get you there. 

[SwampDonkey]

Declination matters if you're compassing. You always set declin. on the compass before compassing over land for that area your orienteering. If you're getting a bearing use the dial on the compass like protractor and put north at north on the map. Don't add or subtract decl. twice by mistake by adding it to the dial and then use a compass that is already dialed for decl. when sighting. The bearing is what the map says as if you were using a protractor. The compass accounts for the declin. if set properly. ;D A guy I know would always compass without setting decl., even without using the bearing from a map. Say go E with all the lines, well his lines were always off by the declination if he was running lines on the same block. You couldn't get that through his head. : It's fine if you're measuring area, the shape and area is the same but it's location if mapped is rotated without adjusting declination.

[caveman]

IJohnsaw is right.  I remember it as west is best and east is least, adding for west and subtracting for east, assuming plusses are better than minuses.  

[caveman]

 

 
16.  What is the feature where the black dot is (arrow pointing to)?

[Ljohnsaw]

A saddle or pass between the peaks.

[rusticretreater]

A gap, a pass or a Col.

[caveman]

Answer to #16 was saddle.


17.  What is the elevation of the point A?
        18.  What direction does the perennial stream shown in section 19 flow?

[dogone]

   I remember the days before gps. On the Beaufort sea we precision navigated with loran or shoran. I believe there was also a decca system. In winter we had supply planes navigate with dead reckoning and celestial compass. They would find us on the arctic ice over 250 miles from their base. And land in the dark.
   Later in life I was a bush pilot. Really liked map reading and finding some obscure point .
    Now all pilots just punch in coordinates and follow the track.

[Andries]

hey, @dogone! Another glaciated Canadian that spent their working life North of 60.
Good to meet you, from a guy that spent most of 38 years doing Arctic marine surveys.
Were you with Borek Air?
Kyle: 130 elevation and N0rth?

[Ljohnsaw]

17.  North
18. 130 feet

[dogone]

hey, @dogone! Another glaciated Canadian that spent their working life North of 60.
Good to meet you, from a guy that spent most of 38 years doing Arctic marine surveys.
Were you with Borek Air?
Kyle: 130 elevation and N0rth?

Spent 70s doing land and sea seismic in north. Marine seismic out of Tuktoyuktuk and land in delta. Two winters off Ellef Ringness Island. We had Borek flying for us out of Resolute Bay. Did my flying in n. Sask. 
    Point of interest: worked in Sinai desert in Egypt. Right beside Gaza.

[SwampDonkey]

We also call that a divide up here, drainage can run one way to one brook or the other way to another. Looks like two major gullyes there.

[caveman]

Andries and IJohnsaw were spot on.  I enjoy reading about the experiences of the FF members.  

[caveman]

 

 
#19.  How much elevation change is between .A and .B?
#20.  What do the light green circles that are shown on much of this section of the map represent?         

[Magicman]

Looks like A is 230' and B is 250'.  Foliage.

[Ljohnsaw]

Hmm, looking at the lines to the left of A along the road, it looks to me like A is lower than the 200 line. I put it at 140'? Not sure what those hash marks mean on the lines.

B could either be 100 or 300. Since there isn't a water feature indicated, thinking 300. So the total elevation change is 160'?

20. An orchard?

[Magicman]

100' elevation is in the lower center so A & B should be higher than 200'.  I see them as the higher points on the map.

I actually did not see the green circles until I enlarged the map so...??

[beenthere]

A is 140' and B is 300' the way I am seeing it.

[NE Woodburner]

#19: Question is elevation change between A and B and I see A at 170' and B at 250' so 80' elevation change?
#20: Green dots represent vegetation/wooded areas?

[caveman]

#19 is .A=170', .B=250' with a difference of 80'.  Woodburner got it.  
#20 answer is indeed an orchard. IJohnsaw nailed it.  
 
Most of the time in my neck of the woods, an orchard is a citrus grove (which really is not a grove), or at least it used to be.  A few farmers tried peaches, but fruit flies, not enough cool nights to make them sweet some years plus our market is generally over when others come in made them a tough crop to grow for profit.  Often when walking in the woods in central Florida I've come across hammocks with sour orange trees growing in them.  I suspect these were areas Indians used to live on or at least frequent.  I've eaten some of the fruit from these trees over the years but never tasted any that weren't incredibly sour.  I do not recall ever seeing any of these trees with symptoms of Citrus Greening (the disease that has devastated the citrus industry in Fla.)  Maybe the Asian Citrus Psyllid, the vector of greening, has not found them yet.

We had the county FFA citrus judging contest yesterday in Frostproof, Fl.  Our team did well.  They still have some citrus groves down there.  Our county is roughly 1800 mi2 and Frostproof is a haul from my place.

[SwampDonkey]

My grandfather had his very first hunting camp back in the 20's on one side of a divide. The brook he was on flows into the Saint John River. You could walk a ways in another direction and hit the head of another brook which flowed into the Tobique River. In fact he followed an old road from town out there, a brook flowed along to town for their water source, town was on the Saint John R. You'd hit the head of the brook and be heading down into another brook that went into the Tobique down to the left, but that went out to the divide to the right and up hill, then you dipped down again in to where the camp was on that next brook, which eventually hit the Saint John. And maybe a couple miles east of that road near that divide and the land divided again and water goes to the Miramachi River. Nothing is ever a straight line unless like yours, one gully falling away from the other. It probably looks like cotton clouds the way the contours go. :D There's steep climbing on those hills for sure. Travelling the gullies and creeks was a lot less steep than up over. :D It's nowhere near that hilly around my place, near flat, although I always said I was on a side hill, but easy side hill. Everything flows down hill from the front door. :D

[peakbagger]

Up in the mountains of NH, we have some topo map situations that are probably not in Florida. Situation one is when the contours lines are touching each other. That means cliffs and in some cases, overhanging cliffs. Second situation is white areas in combination with contour lines nearly touching, that means bare rock with little or no vegetation. Generally place to avoid when bushwhacking cross country although some folks seek them out as they frequently have great views from up at the top. 

[caveman]

I have an old book of topo maps somewhere.  I recall seeing some with the lines touching or nearly touching each other and the contour interval being 100'.  These maps were not in Florida.  The highest elevation that I know about on peninsular Florida is 312' at Iron Mountain on the Lake Wales Ridge.  It is the site of Bok Tower.   Bok Tower Gardens, surrounding the tower, was designed by Fredrick Law Olmstead.

?#21.  Which is likely the most famous park designed by Fredrick Law Olmstead?  

[Ljohnsaw]

Shot in the dark: either Golden Gate or Central.

[caveman]

#21 answer (IJohnsaw again for the win)- Central Park

[Old Greenhorn]

Enjoying this thread even if I am not participating heavily. I think reading a topo is a basic skill which should be taught in all schools. I've spent many hundreds of hours pouring over maps, laying routes, and learning terrain before I enter into an area. I used to print out custom topos for my scouts and get them to sit down before a trek and look and the map and have a discussion as to what they could expect to find on the path we would follow. I'd also break that map into sections and each morning hand the leader his map for the day to work from. By that time, they knew all the symbols and could read the terrain. When the trail got confusing, we would stop and try to find where we were exactly on the map based on the terrain we could see around us and points we could site for a back azimuth. I sure hoped they learned something. ;D
 Anyway, they have always been fun for me, and a resource I would not want to be without while in the woods. I have not seen the gridlines on out topos that you have on yours and knowing the plot size was never something I had learning up in. SO I learned a little there. I'll have to see if they are putting grids on our maps here now. All my maps are 'old' like me, they don't change much (also like me).

 Funny story and this is before GPS. My Boys had planned a 'spring trek' of about 25 miles or so through our mountains here, some of the nicest hiking trails in the country. Since it was an extended backpacking trip in the shoulder season across a series of peaks, water was a concern, there ain't none up on top to be found except snow melt, which you can't depend on in that season. So in the month prior to the trip I did a series of solo hikes up the cols to various spots along our planned route to cache water jugs. I noted these on the map for them to find as part of the skills application. Well, I was on one of these cache hikes carrying about 60# of water and found a spot and hid it. That day and that trail was almost all ice after I hit a certain elevation and I put on my ice spikes to get up it. On my way down I had just gotten to the large flat rock where I put my spikes on going up, and I took them off. Directly, a group of young men, about 25 y/o were coming up the trail and we chatted. I noted they had some new gear, in fact it all looked new. One fella says "this trail goes up to the top and then where does it go?". 'Well, I said, it ends at the Devil's path Trail, which goes east or west.' "Oh, well which way to the trail shelter?". I explained there was one in either direction. They looked puzzled and were trying to decide which way to go. So I took out my map to show them the distances and other details. As I pulled it out of my shirt pocket, one of the guys says "Oh HEY! LOOK! he has a map, that's pretty cool!" I look at them, stunned. I ask them "It's March, there is Ice everywhere and you guys started out on your hike without a map, or a plan, or even knowing whether to turn east or west at the top? You have all that new gear and you couldn't go an extra $5.00 for the next most valuable thing than water? REALLY?"
 "Oh they said, we have a plan, we just didn't find one of those maps. Probably be handy to have next time." I chuckled "yeah, ya think?"
 I wished them luck and headed on down. Darwinism at work, that.

 Sorry if I crashed the thread, but map reading is a vital skill, so seeing it discussed and practiced here is a valuable thing.

[peakbagger]

 

 They did themselves a favor and covered Table Rock with a contour label. 100 foot primary contour intervals 40 foot secondary. It hangs out over the face of the cliff looking down at the road. It is about 4' wide at its tip, nice place to hang out on a nice day with a shear drop on either side. Quite a ride through the notch in the winter.

[Big_eddy]

And not a bad view of the Balsams resort from the top.

[caveman]

 

 
#22.  What does the long dash with the short dash repeated, that the arrow is pointing to indicate?
#23.  1320'= ________ Chains
#24.  If a rectangular tract is 20 chains x 40 chains, how many acres is the tract?
#25.  If planting pines on the tract above (#24), how many trees will be needed if planting on a 6'x10' spacing?

[beenthere]

22 county line
23 20 chains
24  80 acre
25  58,080

[caveman]

Beenthere beat everyone to the punch.  Good job!  I had originally done it with a tract that would have been 60 acres (20 ch x 30 ch) but that would have resulted in 43560 trees, which could have been confusing since that is the number of square feet in an acre.

[SwampDonkey]

A chain is the width of all mapped crown reserved roads up this way. 66 feet, which is roughly 20 meters. These are rights of way to property that were surveyed back in the day. Most of them are not even marked in the woods. I've seen some being marked down the middle sometimes, they (woodlot owner) don't own to the middle.

[Sod saw]

.


SwampDonkey,   A 66 foot wide road is 4 rods wide.

Many of our roads down here are 3 rods wide.  49.5 feet wide seems like a weird number until one realizes that is how the roads were laid out many years ago when metal rods were actually used for measurement. 

Mount Everest was surveyed using a Rod made of metal that was shaded by natives who carried umbrellas to keep the sun off so it would not expand and contract as it warmed and cooled, throwing off its length.  When satellite measurements were recently used it was noted that those first early surveys using metal rods were only off by some feet near the top.

Before those times fish were the common unit of measurement in old deeds and survey maps.  (I have to wonder what species of fish were used as the common size.   :D  )

I have a small chart, on the wall near my drafting table, with those conversions because I can not remember them all.


.

[caveman]

#26.  How many links are in a Gunter's Chain (chain)?
#27.  How long is a link?_________"
#28.  How many rolls of barbed wire would it take to put up a five-strand perimeter fence around a standard section?              (A lot of you keep cattle and I assume you know how long a roll of wire is).

[beenthere]

26 100
27 0.66'
28 80

[SwampDonkey]

Yup, and 4 rods = 1 chain. They are 66 foot right of ways up here.

This link only talks about crown lands (public land) because it's an NRED site. Same applies to CRR crossing private land. CRR are owned by the government anyway. The link also makes this statement about cases where they are disposed (sold off). "The Minister can dispose of CRRs not required to provide access to Crown Lands and resources, or private lands" . Then, "In order to apply for the disposal of a Crown Reserved Road you must be an adjacent landowner of the Crown Reserved Road."

Crown Lands - Reserved Roads

[Machinebuilder]

Interesting, Where I grew up in Marilla, NY there is a 2 Rod road, a 3 Rod road and a 4 Rod road.

I remember hearing that they were named after surveying things.

[caveman]

Beenthere got #'s 26, 27 and 28.  A link is .66' or 7.92".  

[caveman]

 

 
29.  Identify the the two black symbols near the top of the picture. ______and _________
30.  What do the ovals represent on a map?
31.  What do the diagonal crosses represent?
32.  Explain the difference between a large cemetery and a landing strip.
33.  What do the two, 2nd from the bottom indicate on a map?

[Ljohnsaw]

29. School and church
30. A paved race track an a dirt track  :D
31. Air field - paved and dirt?
32. One has more bodies buried in it.
33. Camping ( or a reservation) and a picnic area.

[caveman]

Right on.  The landing strip looks about like a large cemetery except is lacking CEM.  

  

[caveman]

 

34.  What does the 3rd one down represent?
        35.  "                   " 5th one down represent?
        36.  "                    "  7th one down represent?

[Ljohnsaw]

34. Year round creek/stream
35. Bigger stream/river - boatable?
36. Rapids/Swift water river

[caveman]

Look at #34 closely, #35 is a perennial river, #36 first mark is small falls and second is small rapids.

[customsawyer]

This came across my one of my Facebook groups the other day. I sent it to caveman and he asked that I put it on here. Rather elementary for what he's asking on here.



 

[caveman]

Thanks, Customsawyer.  Also, we are still awaiting a correct answer for #34.

[clearcut]

Disappearing Stream #34

[caveman]

Clearcut got it.   smiley_hollywood_cool

[caveman]

Look at the third one down.  It looks a bit like a disappearing stream, but it is not blue.
37.  What is it?
Cedarman ought to be all over this one. 

[Treefarm1]

The symbol is "Mine tunnel or cave entrance." I didn't recognize it either, but I have never seen a cave or mine entrance on the areas I've been with a topo map.

I'm a retired service forester in Wisconsin. Lots of air photos and digital topo maps are available on many of the county GIS websites here in Wisconsin and I suspect elsewhere too. For many years the primary air photos I used were from the Farm Service Agency.

https://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf

[Texas Ranger]

Welcome aboard Treefarm1 from another retired forester, although a consultant and in Texas!