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Gmane
From: Hamish <hamish_nospam-/E1597aS9LQAvxtiuMwx3w <at> public.gmane.org>
Subject: Re: [ gpsdrive ] Routing
Newsgroups: gmane.comp.linux.gps
Date: Wednesday 30th May 2007 11:20:15 UTC (over 10 years ago)
> Clendon Gibson:
> > So I am new to all of this and am only just now getting to the point
> > of installing gpsdrive onto my PDA. I was reading over the features
> > and noticed that for routing there were no plans since commercial
> > map data costs so much.
> >
> > I was wondering if anyone had taken a look at the work done by dan
> > at logical genetics with free map data and software. Apparently the
> > us government has map data for the entire world that they make
> > available for download. (Some of you have apparently DL'd the maps
> > from NASA.)
> > http://www.logicalgenetics.com/showarticle.php?topic_id=1173&page_num=0

Joerg:
> Well; there is a probably more apropriate Source:
> www.openstreetmap.org. We  are currently favorizing this dataset
> because it's not only US, but will  cover the whole world `pretty soon
> ;-)`

NASA map data we are using is the Blue Marble 2002 raster, nothing to
do with roads, just pretty pictures from space.

World-wide road data from US Defense Map Agency is the famous Digital
Chart of the World dataset (aka Vmap0). It's free, but at 1:1 million
scale -- generally way too crude for our needs. This is what Logical
Genetics is using.

There is the high-resolution US-only TIGER road data from the US census
bureau. IIUC the OpenStreetMap people are loading this into the OSM
database, everyone (in the USA) wins! Not sure how far along with that
they are.

> > Of course the map data is only the start. We need routing software
> > after that.

GPL routing software is available in GRASS GIS's v.net.* modules.
screenshots:
  http://grass.ibiblio.org/grass61/screenshots/network.php
  http://grass.ibiblio.org/grass60/screenshots/vector.php

Shortest path (including differing costs for different classes of road),
travelling salesman problem, etc. Vector format is topological, ie you
can have 3D bridge overpasses without creating an intersection at the
x,y cross. One way roads are supported. We recently added some new
examples to the help pages for d.path and v.net.path in GRASS 6.3cvs.

My idea for a GpsDrive prototype was to use the GRASS d.out.gpsdrive
module to output new maps on-the-fly (overwrite predefined grid of
tiles?) with highlighted path drawn on top. It's absolutely 100%
possible right now, I just haven't spent the time to do it. OSM data
coverage is very poor in my part of the world which doesn't help, and
I spend more time on boats than in cars.

In GRASS you can also do r.in.wms and fetch data from any WMS server,
which is likely somewhere to have the TIGER data, or just load the TIGER
or Vmap0 data into the GIS with v.in.ogr. (then zoom + d.out.gpsdrive)

for a start at loading OSM data into GRASS & setting up the network see:
  http://hamish.bowman.googlepages.com/gpsdrivefiles
 (I've also not spent much time on this)


Hamish
 
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