<html><head></head><body>6.4.3 sorry about not including that from the start.<br><br><div class="gmail_quote">On August 28, 2014 3:42:45 PM EDT, Markus Neteler <neteler@osgeo.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">Jim,<br /><br />please post your GRASS version to the list to better help.<br /><br />Markus<br /><br />On Thu, Aug 28, 2014 at 1:40 PM, James Keener <jim@jimkeener.com> wrote:<br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> I'm trying to create a map with isolines for the road-distance places<br /> are from bus routes. I was trying to roughly follow<br /> <a href="http://jcastellssala.wordpress.com/2012/05/07/basic-network-analysis-with-grass">http://jcastellssala.wordpress.com/2012/05/07/basic-network-analysis-with-grass</a>/<br /> but I don't quite get similar results (I feel like the network isn't<br /> completely connected, but this is the first time I'm doing this so it's<br /> more likely I'm just doing it wrong.<br /><br /> I am using the following shapefiles in SRID 2272 (NAD83 / Pennsylvania<br /> South (ftUS)):<br /><br /> <a
href="http://jimkeener.com/grass-topo-question/roads.tar.bz2">http://jimkeener.com/grass-topo-question/roads.tar.bz2</a> which is the<br /> TIGER road graph for Allegheny County, PA, USA (state fips = 42, county<br /> fips = 003), but reprojected to 2272 and a "length" attribute added.<br /><br /> <a href="http://jimkeener.com/grass-topo-question/stops.tar.bz2">http://jimkeener.com/grass-topo-question/stops.tar.bz2</a> which is derived<br /> from the Port Authority of Allegheny County GTFS file found at<br /> <a href="http://www.portauthority.org/paac/CompanyInfoProjects/DeveloperResources.aspx">http://www.portauthority.org/paac/CompanyInfoProjects/DeveloperResources.aspx</a><br /> and reprojected to 2272.<br /><br /><br /> So, the first thing I did is import these files:<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> <a href="http://v.in">v.in</a>.ogr dsn=roads.shp layer=roads output=roads<br /> <a
href="http://v.in">v.in</a>.ogr dsn=stops.shp layer=stops output=stops<br /></blockquote><br /> (<a href="http://jimkeener.com/grass-topo-question/ac.png">http://jimkeener.com/grass-topo-question/ac.png</a>)<br /><br /> Then I connect the stops to the network<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> <a href="http://v.net">v.net</a> input=roads points=stops output=network operation=connect thresh=500<br /></blockquote><br /> Connect the require database layer<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> v.db.connect map=network table=schools layer=2<br /></blockquote><br /> Then allocate the network<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> <a href="http://v.net">v.net</a>.alloc --overwrite --verbose input=network
output=network_alloc ccats=1-6965<br /></blockquote><br /> (<a href="http://jimkeener.com/grass-topo-question/ac-alloc-zoom-thumb.png">http://jimkeener.com/grass-topo-question/ac-alloc-zoom-thumb.png</a> when<br /> displayed with d.vect -c) (the little Xs are bus stops<br /><br /> And create isolines at 1-, 2-, and 3- thousand feet<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> <a href="http://v.net">v.net</a>.iso --overwrite input=network output=network_isolines ccats=1-6965 costs=1000,2000,3000 afcolumn=LENGTH abcolumn=LENGTH<br /></blockquote><br /> (<a href="http://jimkeener.com/grass-topo-question/ac-isolines-zoom.png">http://jimkeener.com/grass-topo-question/ac-isolines-zoom.png</a> also with<br /> d.vect -c)<br /><br /> All but a few of the roadways near the open space to the right (a park<br /> and very hilly (even by Pittsburgh standards:-p) area) are within 3000<br /> feet of a bus stop.
Therefor I was expecting almost all of the roads to<br /> be highlighted in different colors representing their distance from a stop.<br /><br /> Thank you for any help!<br /> Jim<br /><br /><br /><hr /><br /> grass-user mailing list<br /> grass-user@lists.osgeo.org<br /> <a href="http://lists.osgeo.org/mailman/listinfo/grass-user">http://lists.osgeo.org/mailman/listinfo/grass-user</a><br /></blockquote></pre></blockquote></div><br>
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