Re: [seul-edu] Free USGS topo maps online

[lp <prevettl@cochise.cc.az.us>]

Jonathan Byron wrote:
> 
> There are several GIS projects in the works that are GPLed or otherwise
> free. Start with www.freegis.org for pointers.  GRASS is the one of the
> oldest and best known free GISs - it was started by the US Army Corps of
> Engineers, and then spun off to the public when the commercial GIS firms
> convinced the politicians that the government had no business creating free
> software that took bussiness away from the $10,000 a copy GIS vendors. GRASS
> works primarily with the raster data model, and has very limited vector
> support.
> 
> The topo maps that you mentioned are actually scanned images of the maps
> (raster images) - they do not have the geographic information like
> coordinates, projection info, or attributes built into the data except as
> colors that humans interpret. It would take some work to get these maps into
> a real GIS.  There are other topographic data formats that are available
> free, like the Digital Line Graph, or DLG - this is a vector form where each
> geometric object (like a road or contour line) has a link to a database, and
> properties like the name of the road, speed limit, or elevation.  There is
> less Free Software available for vector files, but look at MapServer,
> Practical Map Server, and OpenMap for starters.
> 
> And yes, we do need development of better Free (TM) GIS software!!
> 
> Jonathan Byron
> Assistant Professor of Geography
> Jacksonville University

We installed Grass5 and got it to run in RH6.2. We went through
the Grass Seeds tutorial which gave us a better idea of what it 
would do. We are trying to organize a 1/2 credit hour class to 
introduce students to GIS concepts (we don't have a $10,000 
budget for GIS software - that stuff is really expensive!)

Here's the link for the tutorial.

http://www.geog.le.ac.uk/assist/grass/seeds/gs_html.html

In X Windows on the desktop, you have a console open for 
GRASS commands, one or two graphics windows for map overlays, 
etc., and another a browser for the tutorial. Some of the 
teachers that we showed the tutorial to were impressed that
you could get that many things comfortably on a desktop. It
was a perfect example of how wonderful Linux is for science
and math applications.

L. Prevett
Mathematics Instructor
Cochise College, Sierra Vista, AZ, US
prevettl@cochise.cc.az.us