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Old 04-18-2008, 10:37 AM   #1
colden46's Avatar
Join Date: Oct 2006
Posts: 1,059
Mapping public vs. private land

Hi all, for the folks that didn't see the "Topozone replacement" thread from the Mapping & GPS forum, I put together a little web site that allows you to search for USGS place names and then view USGS topo maps of the results in a Google Maps interface. As the name of the thread suggested, it was basically to re-create since that is now a pay site.

Well, after getting the basic maps working I thought it would be cool if I could add an overlay to the map showing public vs. private land. I have a couple park-wide maps that show this, but since they cover the whole park everything is tiny on the map. On the website you can see in much better detail. I assume I'm not the only one looking for this type of information, so I thought I'd post a note here. Private land is shaded darker on the map, whereas public land appears normal. You can check it out at:

A couple caveats: first and foremost, I got the data from the NYS GIS website, and it's around 10 years old (despite the fact that on the site it says the data is updated annually). This means that a lot of major purchases that have happened since then still show up as private land. The one that jumped out at me the most was Little Tupper Lake. The APA has some updated data on a CD, but according to their website it's still only from 2001. I'm waiting to hear back from someone there about getting more up-to-date stuff.

Second, the data considers water as a separate category, neither public nor private. That's why lakes aren't shaded, even if they're surrounded by private land. As you can also see, the data doesn't line up perfectly with the underlying maps, so if you zoom way in you can see a bit of difference along the lakeshores. The lesson here is, it's not perfect -- and if you use this and end up getting arrested for trespassing, don't blame me

Third, it's really difficult to see the shading if you switch to the satellite view.

Let me know if you have any problems. Thanks!
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