[GRASS-user] visualizing transit times as a map layer

[Michael Barton]

On Jan 9, 2010, at 10:00 AM, grass-user-request at lists.osgeo.org wrote:

> Date: Sat, 9 Jan 2010 11:01:23 -0500
> From: James Kebinger <jkebinger at gmail.com>
> Subject: [GRASS-user] visualizing transit times as a map layer
> To: grass-user at lists.osgeo.org
> Message-ID:
> 	<6d88dde21001090801w642fcc3fse3b8a2cfba10e402 at mail.gmail.com>
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> 
> 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