I need to merge about 760 png files into one and am looking at using gdal for this. This is related to the following question Getting a constant background color for transparency
P:\2012\183_TownPlanning_Symbology\Working\Raster_Layer_Creation\tests\BA\25k>gd al_merge -o ba_25k_gdal -of png -init "255 255 255" *.png
should work but gives
Format driver png does not support creation and piecewise writing. Please select a format that does, such as GTiff (the default) or HFA (Erdas Imag ine).
When I switch to HFA or GTiff format and try
P:\2012\183_TownPlanning_Symbology\Working\Raster_Layer_Creation\tests\BA\25k>gd al_merge -o ba_25k_gdal -init "255 255 255" *.png
ERROR 4: `*.png' does not exist in the file system, and is not recognised as a supported dataset name.
Traceback (most recent call last): File "C:\OSGeo4W\bin\gdal_merge.py", line 509, in sys.exit(main()) File "C:\OSGeo4W\bin\gdal_merge.py", line 392, in main ulx = file_infos.ulx IndexError: list index out of range
but the format seems correct according to http://www.gdal.org/gdal_merge.html
How can I tell it to include all png files in the directory? I can pipe *.png > png_list.txt but can I get gdal to read a list from a text file? So does this mean merging png's in gdal is not possible?
Are there other ways of achieving this? I have tried Global Mapper but that estimates a day to complete it and I am just running it. Erdas crashed. I am trying ArcMap 10.1 import into mosaic dataset and export as raster -still running but estimates a 35gb png file.
This is from 161 tiles (25k resolution) over 65,000 sq km. But the source png's are only 73Mb.