Online Large Topo Maps?

[+ExTechOp]

We will probably be visiting New England some time in the autumn, and I'm looking for good digital topo maps of the region. As the trip will be at most a couple of weeks, I would prefer not to buy software which will probably be obsolete by the next time we visit.

 

Here in Finland, the cheapest (free!) way to get high-quality digital topo maps for use in a PDA or such equipment is to access the National Land Survey website "Citizen's MapSite" using a piece of python software called fetch_map which extracts the map squares, removes the watermarks, and combines the small image squares into a larger calibrated map which can then be loaded into your equipment with OziExplorer or similar software.

 

Is there a similar piece of software to extract info from the USGS TopoZone or other similar online maps?

Edited July 15, 2006 by ExTechOp

[+Timpat]

You can accomplish what you described with USAPhotoMaps. It accesses the USGS topo maps from TerraServer. In the Help section of the free software there are steps on how to create "Big" map sections that are saved a .jpg images. Briefly, you would go to the area of interest and zoom to the 4 meter level (best detail), and move the cursor to a corner of the extent of your coverage wanted. Depress the mouse and hold, then pull a "box" to the opposite corner. When you reach the edge of the screen, use the up/down/left/right arrow keys to "stretch" the limits of your Big topo map. It works very cool!

 

These are projected in UTM (meters) and it creates a world file if needed. Not sure how you plan to use them on a PDA, and I'm not up to speed on them, but you could at least create fairly large area topo maps to display. I create these for use in GIS where I need georeferenced topo maps. Hope this helps, and welcome to New England!

Edited July 15, 2006 by Timpat

[edmcnierney]

Welcome to New England, too! You should be aware that Microsoft's online maps do not cross UTM zone boundaries, and there is a UTM zone boundary running right up the middle of New England. You're more likely to encounter this problem if you're making large maps, since they're naturally more likely to cross the boundary.

 

TopoZone maps correctly cross UTM zone boundaries. Our TopoFactory service (not free) lets you create and download custom, seamless topographic map images that can be very large. And you can view and print 8.5x11 maps for free anywhere (including along zone boundaries).

 

If you can avoid the zone boundary the free stuff may work fine. Microsoft also has a number of errors in their topographic map data, but unless you run into one you can ignore them. You should just check them out well in advance so if they don't work out you have time to look for alternatives. One of the CD-ROM topo map products might work well, too.

 

Ed

 

Ed McNierney

TopoZone Map Guy

[+apsyrtes]

Is there a similar piece of software to extract info from the USGS TopoZone or other similar online maps?

 

You can download your USGS topo maps and various other map data here:

http://datagateway.nrcs.usda.gov/NextPage.asp

 

Although it talks about "putting together an order" there is no fee for the order.

 

You can then use OziExplorer's MapMerge (free on the OziExplorer site) to stitch them together into as big a map as you want. Will that accomplish what you are looking to do?

[edmcnierney]

You can then use OziExplorer's MapMerge (free on the OziExplorer site) to stitch them together into as big a map as you want. Will that accomplish what you are looking to do?

I think that will do what the OP wants, except that the free MapMerge utility produces output images in OziExplorer's proprietary format that must be used in the non-free OziExplorer software. OziExplorer is good stuff, so that might be what you want, but the proposed solution does require the purchase of OziExplorer software.