[Xastir] US Topo GeoPDF?

[Tom Hayward]

On Sun, Mar 18, 2012 at 10:32, Lee Bengston <lee.bengston at gmail.com> wrote:
> On Sun, Mar 18, 2012 at 12:16 PM, Tom Hayward <esarfl at gmail.com> wrote:
>> I just discovered the USGS US Topo map download site
>> (http://nationalmap.gov/ustopo/index.html). In the past I have used
>> USGS Topo quads in geotiff format, but these downloads are "GeoPDF".
>> It doesn't appear Xastir supports this format. Did I overlook
>> something? How difficult would this be to add?
>>
>> Tom KD7LXL
>
> Fyi, Tom Russo added a script a while back that converts the geopdf's to tiff.

Thanks, I didn't realize this problem had been solved. Unfortunately I
have not been successful in building gdal for OS X. I'll have to try
with Ubuntu later; OSS tends to build more smoothly there.

In the meantime, I've found a source for the classic GeoTiff USGS quads:
http://libremap.org/data/

I notice two things about the GeoTiff files: the borders aren't
cropped, and the datum is translated from NAD27->WGS84.

Where does the crop data come from for the GeoTiffs? I see
geopdf2gtiff creates crop data, but I would need to get this script
working to utilize this.

I understand Xastir is fixed to WGS84 (like all of APRS). My SAR team
reads UTM coordinates from the map, which in this case is NAD27. Not
everyone has APRS capability (actually, it's just me :). This leaves
me with no good way to plot coordinates in Xastir without first doing
a datum conversion with some 3rd party software. Is there a better
solution?

Tom KD7LXL