On Jan 9, 2010, at 10:00 AM, grass-user-request@lists.osgeo.org wrote:
Date: Sat, 9 Jan 2010 11:01:23 -0500
From: James Kebinger <jkebinger@gmail.com>
Subject: [GRASS-user] visualizing transit times as a map layer
To: grass-user@lists.osgeo.org
Message-ID:
<6d88dde21001090801w642fcc3fse3b8a2cfba10e402@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"Hello grass users - I've got a beginner level question for you.
I've generated a csv file containing latitude, longitude, and transit time
to a location in the Boston metro area. I'd like to load this file as a map
layer and visualize it as a heatmap-style visualization.
How do I get started with GRASS to do such a thing? Is it possible to import
this type of file, or is there a step I have to do (rasterizing?) prior to
starting with GRASS?thanks!
-James
Use v.in.ascii (file/import vector map) to import the points. Then use any one of the several interpolation routines to create a continuous surface from the transit time values (eg, v.surf.rst, r.surf.bspline, v.surf.idw - raster/interpolate surfaces [using vector points]). Read the online help for each module to see how they work and which is best for your purposes.
Michael