I have three ASCII files: 1) pixels values, 2) upper left corner longitudes, and 2) upper left corner latitudes. All three files are 1350 X 1350, left-to-right, top-to-bottom. The coordinates are in a polar stereographic projection with a 4.5km resolution
(‘ +a=wgs84 +proj=stere +lat_0=70.0000000 +lon_0=-45.000000’). I tried using "Geoference with IGM", but I either get an error, often "an attempt to subscript DXS was out of range" or there is an output grid of 77 X 2330, with a weird arrangement of values.

Am I missing something? Is there another way to georeference with these data formats? Thanks! Anything helps!