[gdal-dev] reprojection from BNG to WGS84 -- using gdalwarp

[Andreas Joisten]

Hi all,

I have problem to reproject a raster file in BNG British National Grid to WGS84.

gdalwarp -s_srs EPSG:27700 -tps -t_srs EPSG:4326 -co TFW=YES -r near input.tif geo_output.tif


I have some questions:

Must be the input file a GeoTiff file? 
Which requirements must be met by the input file?
If the input file is a GeoTiff, do I need ground controlpoints?



Thanks for help.