[FOSS-GPS] FoxtrotGPS Mapping Library

[Jay R. Ashworth]

----- pcreso at pcreso.com wrote:
> My 02c :-)

Marked down for inflation, of course.  :-)

> As a long time FOSS GIS user (who used to work with pre-satellite
> fixes, then transit data, & at last, real GPS data!!), one thing I
> miss with most GPS software is the ability to natively utilise
> standard GIS data formats.

Oh, yes.

> I can gather free topo, depth & road data, build my own maps with FOSS
> tools like GRASS, R & GMT. Build my own shapefiles & geotiffs, manange
> my data in PostGIS or SpatialLite, etc. But having done all the hard
> GIS work, none of the products (such as geotiffs, or png/world file
> combinations) can easily be used with a GPS software tool.

Well, not necessarily directly, no, but -- as another reply points out -- that
is as much as for any other reason because the target platform for programs
like FoxtrotGPS goes down the horsepower scale as far as it does; clearly, some
optimization, trading time and horsepower for space, is called for in those
environments.

That said...

> I'd love to see support for world file image tilesets, as used behind
> web mapping applications such as Mapserver; shapefiles, spatial
> databases like PostGIS & SpatialLite from a GPS application.
> 
> Generally just better integration/interoperability between the FOSS
> GIS & FOSS GPS arenas.

You and me both, Brent, and it's one of the directions I'm investigating.

The current implementation of Foxtrot expects to retrieve tiles from an
internet map tile server, using NASA Worldwind URL protocol, or anything
that looks a lot like it, which includes TMS, and *I think*, WMS-C (It
was a couple days ago I was surfing through this stuff, and I'm on a
different computer just now).

Now, all those things said, FoxtrotGPS can likely be coerced (I have not
yet personally tried this) to accept a pre-built tile cache for a map layer
for which it does not have a valid URL to retrieve live tiles.  Additionally,
I saw a script -- I think it was part of the GDAL distribution -- which would 
split GeoTIFF files into Worldwind style map tile files; I assume it gets the
naming/addressing right, but again, I haven't gotten that far yet.

And finally, if what you have is vector data, I understand Mapnik can render 
that out into raster files -- it's a fair bet that Foxtrot will remain a raster
map based program for at least the foreseeable future, unless Mapnik (for example)
is much more processor-efficient than I intuit.

But I am a cartography junkie, and a generalist, and I share your view that
Foxtrot might well be useful for audiences far removed from it's current primary
target audience: people with GPSs who just want to get around, and keep track of
it... and some of my work is aiming in that direction; I invite assistance on
that point.

I'd love to see Foxtrot ship with, or at least include pointers to, toolchains
for building maptile sets from data sources other than those we have now.

Down the road, I'd like to see it become a WMS client, but that, also, is a 
question of horsepower vs space and network speed.

Cheers,
-- jra

-- 
Jay R. Ashworth                   Baylink                      jra at baylink.com
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