access to public information about land ownership

[kepPNW]

How are you converting the vector shapefiles to something GPS compatible?

One way is to convert polyline shapefiles to .gpx tracks as if someone had walked around each piece of property. (If the properties are polygon areas it is necessary to convert them to polylines first.) I do this with Global Mapper. The problem with this method is that for urban fringe areas and large rural areas there will be too many .gpx tracks to download to the GPS receiver.

Another way is to use cGPSmapper and SendMap20 to download vector maps into Garmin GPS receivers. Garmin makes using custom vector maps difficult but it is perfectly legal and IMHO perfectly ethical. My custom maps are entirely made of public domain, non-copyrighted data. And, unlike software where you buy a license, with hardware you can do whatever you please with it. And, I have a licensed copy of cGPSmapper.

I don't have a lot of reservations about using data that I come across. In particular data that's ostensibly public domain. (Just about everything's derivative, in some sense or another, eh?) Not sure I'd want to even think about using parcel data as a bazillion tracks, though! That just sounds like a real mess. Curious about the other format, though. Presumably, that's what they're doing for trail maps? I've wondered how those were made on a custom basis (like EP's mapset or NWTrails).

[Adventure Mapper]

Curious about the other format, though. Presumably, that's what they're doing for trail maps? I've wondered how those were made on a custom basis (like EP's mapset or NWTrails).

One way or another you need a .img file. For old GPS receivers like mine you need a special downloader, SendMap20. For the new ones that look like a memory device on your computer you just put the .img in the right place with the right name.

This is how I put 10 ft. contours derived from LiDAR DEMs into my GPS receiver.

[Eric Peterson]

One way or another you need a .img file. For old GPS receivers like mine you need a special downloader, SendMap20. For the new ones that look like a memory device on your computer you just put the .img in the right place with the right name.

This is how I put 10 ft. contours derived from LiDAR DEMs into my GPS receiver.

The newer Garmin handhelds also support Custom Maps which are straight up .JPG's
with an accompanying doc.kml file that holds the geo references I guess.

Garmin Custom Maps

But, yeah, Garmin still uses the .img format for the mapsets. gmapsupp.img

[kepPNW]

But, yeah, Garmin still uses the .img format for the mapsets.

Fascinating! I suppose I could've dug this out, but just haven't run across it before. First search turned up a great starting point, with a skeletal outline of the structure of those IMG files...

http://wiki.openstreetmap.org/wiki/OSM_ ... ile_Format

It also had links to more and better info, though. Thanks for the nudge!

[RobFromRedland]

The newer Garmin handhelds also support Custom Maps which are straight up .JPG's
with an accompanying doc.kml file that holds the geo references I guess.

Garmin Custom Maps

But, yeah, Garmin still uses the .img format for the mapsets. gmapsupp.img

Wow, I guess there is a reason to upgrade the older Garmin units....Cool! Thanks for posting that link!

[Joseph Elfelt]

Merry Christmas All,

Here are a few thoughts after reading the tread.

Have you seen this site? http://www.huntinggpsmaps.com/
Their staff researches all the different kinds of public land (there are many!) and loads that data into their system. I’ve talked to the owner - too bad I don’t live in Missoula or I would go to work for the guy.

ArcExplorer only reads files that you make with ArcExplorer. It does not read shape files or geodatabase.
http://forums.esri.com/Thread.asp?c=24&f=205&t=80851

ESRI has an API that anyone can use to roll their own code to read geodatabase files. You need to write C++ code to use it.
http://resources.arcgis.com/content/geo ... le-gdb-api

If shape files are converted to KML/KMZ then they can be displayed with various software including Gmap4. Bad news: The best way to do this conversion is with the (expensive!) Arc GIS software. Good news: There is a guy who is connected with Back Country Horsemen of Washington who works as a GIS analyst and as a hobby is converting many USFS shape files into KMZs. He is then building links to display those files with Gmap4. As a result you can (1) see the trails on the Google aerial and (2) shift Gmap4 to ‘Earth’ and fly over the trails in 3D - a most dandy and addictive time-waster.

Here is the map he made for the trails in the Mt Hood NF:
http://www.mappingsupport.com/p/gmap4.p ... 8&t=t1&z=9

And here is the rapidly growing map page he maintains:
http://capitolriders.org/maps.htm

Now back to public land.
Lately I have started to search state websites for public land related files that Gmap4 can display. In particular I am looking for files that show the boundaries of wildlife management areas. If I find a file that is a KML or KMZ then Gmap4 can already display those files. I will be adding more of those map links to this page: http://www.mappingsupport.com/p/gmap4_r ... _maps.html

But many public land related files are only online as shape files. Hmmmmm. In order for Gmap4 to display a KMZ file, Gmap4 first converts that file to a KML file and then tells the Google map API to display that KML file. Hmmmmm. Maybe I can use the same approach to make it easy to display shape files. I know there is a utility I can run on my server to convert shape files to KML. No guarantees but I am going to take a stab at implementing this. If I get this working then Gmap4 will easily be able to display many shape files showing public land (or anything else).

I’ll be updating the Gmap4 code in a few days. In part, there will be a much nicer interface when it is running on a mobile device. It will look more like a native app.

Joseph, the Gmap4 guy

[Eric Peterson]

gmap4 Guy, thanks, downloading the free trial now to check out his NorthWest data!

Could be worth his asking price after checking it out.

As far as gmap4, when you say mobile device you mean like a phone and not a
handheld GPS?

[Joseph Elfelt]

As far as gmap4, when you say mobile device you mean like a phone and not a
handheld GPS?

Sorry for not being more clear.

Yes, by "mobile" I mean smartphones and tablets.
Keep in mind that Gmap4 is a browser app.
Gmap4 will only work if your browser is online.

Joseph, the Gmap4 guy

[retired jerry]

I looked at the trails of Mt Hood National Forest and it looks pretty accurate and up to date

Like the trails on Zigzag Ridge are correct - there are some places where Zigzag is incorrect next to Burnt Lake Trail on the classic USGS maps but you have it correct.

It shows the Timberline Trail crossing Eliot where the ropes are, which isn't too bad. That used to be mopre official and they put a little bridge in during the summer.

[kepPNW]

That's some really good info, all in all! I need to do some more looking at a bunch of your links, and in particular at Gmap4. But one point needs correction...

ArcExplorer only reads files that you make with ArcExplorer. It does not read shape files or geodatabase.
http://forums.esri.com/Thread.asp?c=24&f=205&t=80851

Not true. That thread is focused on MXD files, which is what ArGIS uses to store "map documents" composed of various map layers and other things (titles, legends, etc). ArcExplorer can definitely use both Geodatabase data as well as numerous other formats including shapefiles. Here's a link to the options. (Hit "Table of Contents" in the upper-left, to get a full treeview of related content.)

Thanks!