Libremap

[Motabobo]

I see more and more references to http://libremap.org/ which is great but can someone tell me why there is a site like this when all the DRGs (and more) are available for free in each (NE & NY at least) state's GIS official website

 

[sardog1]

Well, the availability of free DRGs varies greatly across the country. New Hampshire is available from GRANIT (sic.) Maine is at Maine GIS Data Catalog. I haven't dug recently for the other Northeastern states; maybe you or someone else from those states can provide links here.

Another source is the federal agencies that use them constantly, e.g., Fish and Wildlife Service, Forest Service, BLM, etc. Scrounge around on their websites, looking especially at site maps.

A Google search for "DRG", limited to a particular state or agency site, is often very productive. It's something of a detective game finding them.

In my experience, searching for "free" and "DRG" sometimes leads to folks who want to sell you DRGs. Sometimes, not always.

 

[Motabobo]

Yeah it's not always easy. Here's what I found :

• Maine GIS Data Catalog
• New Hampshite GRANIT
• Vermont Center for Geographic Information
• New York State GIS Clearinghouse

Any other reliable sources out there ??

 

[DougPaul]

The history as I understand it:

The DRGs (scans of the paper topo maps) were created under contract to the USGS. (The topo maps themselves are public domain.) The USGS, however, did not put the data on a web site/ftp server, but made them available for a fee. Some organizations (eg some states) bought the data and made it freely available over the net. Some other organizations bought the data and charged for it or made downsampled versions freely available and charged for the full resolution scans. In time, a number of the free sites disappeared. So the net effect was that the freely available maps were spotty.

The Libre Map Project, http://libremap.org/, is an attempt to collect pointers to the available free mapping data and data to make it available to the public. Fortunately, they appear to have been rather successful. I believe that some of the people involved are from the open-source software community.

Many other countries consider their government map data to be a commercial product and charge considerable fees for it.

If nothing else, the Libre Map Project website puts links to the maps for the entire country in one place which makes them easier to find than having to search them out yourself. (I have wasted non-trivial amounts of time searching for various maps...)

Doug

 

[JOD]

more...

I use these sites regularly. I create maps with these products daily. I also use the above sites, but didn't feel it was necessary to relist them

MASS-GIS
Rhode Island (RIGIS)
Connecitcut (MAGIC)
NJ DEP GIS
North Dakota GIS
West Virginia
Maryland Mississippi Florida
Utah

have fun mapping!!