BLM map coordinate conversion

JNDEER

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I know we have some serious map junkies out there. How can I take the coordinates on my CA BLM maps and figure out what the decimal degrees are so I know exactly where it is in GE?

Anyone know if there are free files, like KMZ, I can get to paste into GE to show the BLM/NF boundaries?


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JNDEER

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Kind of, but no.

I have the CA BLM maps. They only list some degrees, example one of my maps has 45 and 30 degrees listed on it with R _ _ E numbers. How can I use that information to come up with the information needed to convert them to a decimal form so that I can pin point that exact spot on GE.
 

sierrahunter1

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Ok. I've dusted off a BLM map, and see what you're asking. You're likely to be a bit frustrated with how clunky it is to convert coordinates, but you can do it.

These maps are in Township-Range format. So, for instance, T8N means: Township 8 North. R9E means Range 9 East. The occasional degrees you see relate to Lat Long coordinates. They're not very helpful, because they are Lat-Long for the whole map, essentially. Ignore those at this point.

Let's focus on the Township-Range coordinates. Each Township is subdivided into 36 sections, and each section is one square mile in size. You'll notice that only a handful of sections are numbered on your map. You can interpolate the missing numbers from the ones given, because they are always numbered like this:

[sharedmedia=core:attachments:68007]

Ok, so choose the Township and range you're interested in. On the left hand side of the map, let's choose T8N, and on the bottom side of the map, let's choose R9E. Fantastic. We've narrowed down our area to 36 square miles. Choose the section you want. Let's choose section 35. Now we have identified one square mile. Better than nothing, I suppose.

Alright, then go to this site: http://esg.montana.edu/gl/trs-data.html

Once there, choose the meridian within which your area is located. There are three meridians in CA (San Bernardino is in pink below, Mt. Diablo is in green below or Humboldt, pink again). See below:



[sharedmedia=core:attachments:68008]


Then enter the information in the blanks on the website (Township 8 North, Range 9 East, section 35), and hit "submit".

The very first line of output says, "Latitude/Longitude 38.5031°N, 120.9550°W ( 38°, 30', 11.3" N; 120°, 57', 18.1" W )"
You can enter 38.5031°N, 120.9550°W in Google Earth, and it will take you to the center of the section 35.

How fun was that?!! Sorry it's not easier. Maybe someone else has a better way.
 

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JNDEER

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Sierra you da man. I am working now, but when I get home and can look over the map to see if I can do that I will let you know. That is exactly what I was looking for.


Now, if only the government ran organization could just put all that information online so we could just download the map lines over GE.

On a side note- I pulled up the latest version of gmap4 and it appears ( have not confirmed) that his maps have the overlay of NF, just not BLM.
 

sloth1833

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I have a PLSS add-on for GE. you can turn it on and off just like roads or places. As you zoom in and out different layers turn on and off, down to township, range, section, 1/4, 1/4. When I get to work tomorrow I'll find the link that I got it from and it was FREE!
 

Joseph

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Thanks to "Custom" for mentioning Gmap4. I am the developer of that enhanced Google map viewer.

Below is a Gmap4 link that displays a GIS layer that shows public land in CA that is owned by various agencies. Yellow is BLM. The map also has 2 other overlays turned on that show PLSS data.

To see the map legend and learn more about using the map, please click "About this map" in the upper left corner.

When the map opens it is zoomed in on some BLM land in El Dorado County.

https://mappingsupport.com/p/gmap4.php?ll=38.536744,-120.927019&z=14&t=t4,Ownership_public_land,County_township_range,Section_line&q=https://propertylinemaps.com/p/public_land_map/state/CA/CA_public_land_boundary.txt

To see the master list of public land and related maps that I have produced you can scroll down on this page:
https://propertylinemaps.com/p/public-land-map.html
 

Joseph

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Thanks for the kind words.

For saltwater anything, here are the NOAA nautical charts:
https://mappingsupport.com/p/gmap4.php?ll=37.643958,-105.238069&z=4&t=h,NOAA_nautical_charts&q=https://propertylinemaps.com/p/public_land_map/USA/USA_NOAA_nautical.txt

Zoom in on your favorite area to see more detailed charts.
To search do Menu ==> Search

GIS servers operated by each state have hundreds of layers of data dealing with just about anything that you can show on a map. If the server is 'public-facing' then Gmap4 can display most of that data. For those of you who are GIS savvy, Gmap4 can display any ArcGIS MapServer and ImageServer data. And I just added support (not documented yet) to display data from ZXY tile servers.

Yes, I produced some maps that show California GIS data layers related to saltwater but not sure if I happened to include the layer you want. You can take a look by going to my main public land map page (https://propertylinemaps.com/p/public-land-map.html) and scolling down to the CA maps and check them out.

Again, please read "About this map" in the upper left corner of each map. That "About" info has important tips for using the map. For example, you can click the layer that is 'on top' and see a popup with all the attribute data the GIS server has for the thing that you clicked. The "About" info explains what that means.
 

JNDEER

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Thank you Joseph.

I could not find a way to add those other layers.
 

Joseph

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JNDEER said:
Thank you Joseph.

I could not find a way to add those other layers.
You read the "About" info, right? So you know how to turn layers on/off when you are looking at a Google/GIS map that I produced.

If you want to read up on the Gmap4 documentation, then you can produce your own custom Gmap4 maps that display any GIS layer you want to see. Open the Gmap4 homepage and then click the "GIS Viewer" tab. There are 2 additional links at the bottom of that page with more info.
Homepage: https://mappingsupport.com/p/gmap4.html
 

Joseph

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Happy to help. There is a *ton* of GIS layers on various servers related to the outdoors.

One problem though is that the agencies that maintain that GIS data tend to rearrange it. When that happens, it breaks maps that pointed to where the data used to be. So when you look at some of my Google/GIS maps and you try a layer that never displays anything, that might be the reason.

Here is a peek looking ahead.

Each GIS server can display a web page that is a list of the layers on that server. For example, here is the 'top' index page for a California GIS server:
https://services.gis.ca.gov/ArcGIS/rest/services

Click the first folder "AtmosphereClimate"
Next click the first MapServer: "AtmosphereClimate/CaliforniaRiverStages (MapServer)"

You are now looking at a page that shows 3 layers. The layers are numbered stating at 0.
At or Above Flood Stage (0)
At Monitoring Stage (1)
Below Monitoring Stage (2)
Gmap4 can display any of those layers.

This winter I plan to work on adding a feature to Gmap4 that will let you display the list of layers on a GIS server, click a layer, and it will be added to the map. This will make it *way* easier for anyone to produce their own custom Google/GIS map.

Best way to stay up-to-date is to keep an eye on this Facebook page:
https://www.facebook.com/Gmap4/
 

JNDEER

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Sorry, yes I saw how to add the extra layers. What I could not find was how to add the BLM and NF overlay.

Again, thanks.
 

Joseph

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A lot of the Google/GIS map links I produced have a layer named "Federal_ownership". Turns out that layer does not work since the layer with the data was renumbered on that server from 24 to 23. I will tweak my maps sometime in the next few days.

Meanwhile, here is a map that just displays that layer 23.
https://mappingsupport.com/p/gmap4.php?ll=38.510077,-121.363007&z=9&t=t1,Federal_ownership&rest=http://wildfire.cr.usgs.gov/ArcGIS/rest/services/geomac_dyn/MapServer?name=Federal_ownership&layers=23&transparent=true

And here is the map legend. Scroll down to #23.
http://wildfire.cr.usgs.gov/ArcGIS/rest/services/geomac_dyn/MapServer/legend

You can click inside any colored area for a popup with all the attribute data the GIS server has for that area.
 

Joseph

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I just fixed the layer titled “Federal ownership” on these maps:
National Forest Recreation Map
National Grassland Recreation Map

You can find links to those maps by scrolling down on this page:
https://propertylinemaps.com/p/public-land-map.html

I took a quick look and those 2 maps might be the only ones I produced that include this layer. If anyone sees a "Federal ownership" layer on another map and that layer does not appear to be working, please email me via my contact page:
https://mappingsupport.com/p/gmap4_contact.html
 
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