[Xastir] FAA sectionals

[Curt, WE7U]

On Thu, 24 Mar 2011, Doug Alwine wrote:

> After some struggle I finally have xastir working!  It works fine with tiger 
> maps and USGS topo maps in GEOtiff format.  It will also display FAA 
> sectional charts (also in geotiff) but to get things in the right place I 
> need to convert them from the Lambert Conical Projection to something that 
> xastir can use.
>
> After compiling xastir, soundmodem, and gdal from source and struggling to 
> get things working so far, this seems like it ought to be fairly easy,  but I 
> cannot figure out how to use gdalwarp to solve my problem.

Probably a Tom question, but I'll tell you what I know (It ain't much!):  Xastir wants WGS84 datum, unprojected.

If you have multiples of these, you might want to bring them into a GIS program, stitch them together into one big map, then set to the correct datum and projection, then chop it into pieces again.  That way Xastir will be able to stitch them together properly when you cross edges.

If you just reproject each map individually, you'll end up with triangles of black at the map edges as you cross over from one to the next because they won't fit the rectangles that Xastir can stitch together.  We cheat on the DRG's, essentially warping them on the fly.

-- 
Curt, WE7U.        http://www.eskimo.com/~archer
U.S. Weather Alerts:  Firenet.us, port 14580, filter "t/n e/WE7U-WX"