Georefence a PPM raster with GDAL

Question

I have a PPM with a GEO file but GDAL does not recognize the GEO file.

emwin@weather:~/SPLAT/bin$ cat roeske_bridge.geo 
FILENAME    roeske_bridge.ppm
#       X   Y   Long        Lat
TIEPOINT    0   0   -88.000     43.000
TIEPOINT    7199    7199    -86.000     41.000
IMAGESIZE   7200    7200
#
# Auto Generated by SPLAT! HD v1.4.2
#
emwin@weather:~/SPLAT/bin$ gdalinfo roeske_bridge.ppm 
Driver: PNM/Portable Pixmap Format (netpbm)
Files: roeske_bridge.ppm
Size is 7200, 7200
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0, 7200.0)
Upper Right ( 7200.0,    0.0)
Lower Right ( 7200.0, 7200.0)
Center      ( 3600.0, 3600.0)
Band 1 Block=7200x1 Type=Byte, ColorInterp=Red
Band 2 Block=7200x1 Type=Byte, ColorInterp=Green
Band 3 Block=7200x1 Type=Byte, ColorInterp=Blue
emwin@weather:~/SPLAT/bin$ 

Answer 1

The GDAL portable pixel map driver https://gdal.org/drivers/raster/pnm.html is not aware of GEO files. Write a world file https://en.wikipedia.org/wiki/World_file and save it as "roeske_bridge.wld".

0.000277778
0
0
-0.000277778
-88.00
43.00