markusby Posted April 8, 2002 Share Posted April 8, 2002 Most people don't know this, but digital USGS topo maps are free. Someone in another post that I wrote about my Navitrak wondered where you would get digitized USGS topo maps and stated that they must be expensive. I wrote him back and decided it was a great topic for geocachers that like TOPO maps they can print themselves. Sorry if this is repetitive in the postings but I felt it was worthy of its own topic. If you feel like something is missing, view the whole post - go to http://opentopic.Groundspeak.com/0/OpenTopic?a=tpc&s=1750973553&f=5740990093&m=4070937914 But here is a part of my post: posted April 08, 2002 03:39 PM -------------------------------------------------------------------------------- Hey Harrkev... The answer to your question will amaze you. Your question is: >Where would you get maps for such a beast? >I thought that buying scanned USGS topo maps was expensive. The correct answer is: http://data.geocomm.com/dem/demdownload.html Yes, you can download all the digitized USGS topo maps (saved in a Tiff format, or a GeoTiff... if you use a GIS program like Manifold, it automatically knows all of the coordinates of anywhere on the map) you want for FREE! Yes, for free. Try it. Go to that link, select a state and select a county. If you just want a digitized Topo map, pick Digital Raster Graphics - 24K (if you want 24k scale). You will then have to click the Quad you want. If you go to Toposource, it will tell you the name of the quad at the top when you are at the area you want. You can open this file up in just about any image program you wish, but to make full use of it, spend a couple of bucks and get Manifold - it's the least inexpensive and very comprehensive GIS program available. The link is www.manifold.net Anyway, once you open it in Manifold, you can import waypoints and they will be automatically positioned on the USGS image. You are probably wondering what the other things on that page are other than the Digital Raster Graphics (DRG) files. You can only open the DRG file in any image program... the rest you need a GOS program. The others are: Hydrography is a list of all of the waterways, lakes and rivers in that area. If you had something like Manifold, you could import this, make your own (you can do that anyway), change it, or whatever you want. Landuse - shows all of the folliage and other pertenant things that hapens on land except for roads, pipelines, hydrographyn railroads and wetlands. These I've named have their own files. You can build your own maps to suit your own needs. A USGS topo map is a combination of all of these things. Oh yeah... you can also get DEM's of elevation, too. The purpose of having a USGS topomap in Florida is the same as having one anywhere. THere is a LOT more information on a USGS TOPO map than merely elevation. Plus, I can make my own maps for various things. I can add buildings, bounderies or whatever I want. If someone came up to me and told me he wanted to divide 500 acres into six zones, I could do it on the computer, download it to my GPS and go out and show him how it would look instead of having an expensive surveyer come out and do the work. Sure it might be a meter or two off, but for a visual, it doesn't matter. Quote Link to comment
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