How do you find just the DEM's you really need?

[gfisher]

I took a look at trainman177's request for a map a couple of days ago. It is easy enough to determine that his scenic railroad lies in both Franklin and Essex counties, New York. However, Franklin County alone contains 46 USGS 24k map quadrangles. How can I tell which ones I might need?

The site www.geocomm.com where I get my DEM data mentions a USGS 24k Quad Grid for download in "SHP" format. Is this what I am looking for and what would I need to view this format?

 

[Dermmy]

USGS National Map Viewer: Zoom in to the area required, then use the extensive menu options on the right to show railroads and the quad grid. You can then scroll along the track and d/l exactly the quads you need....

Andy

 

[StorkNest]

Like Andy, I use a site like that, a couple of changes before downloading and get everything in one data piece (or more if too big). I usually remove roads but leave highway symbols and might add town names so I know where I am looking at.

 

[gfisher]

Thanks Dermmy, I found it. Boy do they ever bury the info deep. Wonder why they just don't have an overlay map.

 

[Dermmy]

Thanks Dermmy, I found it. Boy do they ever bury the info deep. Wonder why they just don't have an overlay map.

LOL - what really p$%^^es me off is you get it all set up showing exactly what you want, scroll and lose the quad name overlay. Grrrrrr

Andy

 

[crag_dolomite]

aother DRG source

Hi All
I'm new to Trainz, and will be ordering 2009 shortly, but
I also use www.geocomm.com for some of my DEM's for other uses
and was using Map Link USGS Topo Index for the USGS file numbers
http://catalog.maplink.com/usgs/USMap.html
Then DL the DRG maps from Libre Map Project Data By US State
http://libremap.org/data/

Quantum GIS (QGIS) is a free Open Source Geographic Information System (GIS) to visualize, manage, edit, analyse data, and compose printable maps.
http://qgis.org/

Also, The free TatukGIS Viewer opens most GIS/CAD vector, raster image, and grid file types, most ArcView, ArcExplorer, and MapInfo projects, and projects
http://www.tatukgis.com/products/viewer/viewer.aspx

I have more free viewers and resources if one is interested

Take Care
Craig

 

[crag_dolomite]

RE: Locating DEM's & DRG's

The best source for locating the DEM reference and for free downloads of USGS DRG (GeoTIFF) digital map files is the TopoQuest Topographic Map Viewer!

http://www.topoquest.com/

 

[backyard]

...your forgetting...

All DEM maps are listed with Latitude & Longitude coordinates....

Usually your looking for the coordinates at the lower left-hand corner...

 

[gfisher]

The best source for locating the DEM reference and for free downloads of USGS DRG (GeoTIFF) digital map files is the TopoQuest Topographic Map Viewer!

Good one. Thank you.