Re: libchamplain displaying GIS files.

[Lorenzo Masini <lorenxo86 gmail com>]

Il giorno gio, 16/09/2010 alle 20.06 +0200, Jiří Techet ha scritto:
> Hi Guillemin,
> 
> libchamplain has a fairly flexible system of map sources and renderers
> now. What a renderer does is that based on coordinates it renders a
> bitmap tile which is then displayed by libchamplain. We already have
> one renderer that renders tiles from vector data - it's a renderer
> based on the libmemphis library
> (https://trac.openstreetmap.ch/trac/memphis/wiki/LibMemphis) which
> renders tiles from OpenStreetMap vector files (in OSM format). I would
> expect that there already exist similar libraries for SHP and KML (do
> they?). So if there is a library that creates bitmaps from the shape
> or kml files, it should be fairly easy to integrate it into
> libchamplain.

I think libchamplain is quite far to be a library suitable for GIS
applications because only the mercator projection is supported _(for
now).

Live reprojection for raster data could be done using gdal library, but
I think it's out of scope of libchamplain.

Talking about vector data, I think that every feature could be drawn on
map, but the condition is that coordinate have to be in latlon decimal
format.
Maybe have all features primiteves (like points, lines, splines and
polygons) in libchamplain could help.

On the other side, render country boundaries could be verry expensive.


In the next release I'd like to concentrate on the frontend side of
> libchamplain so this is not my top priority now but of course I will
> gladly accept any patches if someone wishes to work on that.

I'd like to implement on-map pan and zoom controls (something like
google maps). Should them be useful?

cheers
Lorenzo