This is similar to a question asked by someone else, re OS tiles. However, there is a difference!

I have a large number (over 10k) of georeferenced png files which I have mosaicked in ArcMap, but also want to be able to access them in other programs such as QGIS over the web and within a private network using GeoServer. I have tried creating VRT's with them, and sometimes it works, but sometimes it doesn't. It seems that on selecting over 200-odd png's, the vrt stops being created.

Is there a limit on the amount of rasters for a VRT?

The error message is:

The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.

and the code is:

gdalbuildvrt -allow_projection_difference 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/SX.vrt" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/1.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/2.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/3.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/4.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/5.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/6.png" 
"F:/Historic Buildings/GIS/Data/Mapping/Landranger/Raster/15k/Data/SX/7.png"

with an additional +200 similarly addressed png's

I am using QGIS 1.8.0 Lisboa, on Windows 7 64bit.

2 Answers 2


See if you can do it sucessfully with a handful of files.

For me, it worked with 300 files. At first, I had to build individual vrts for each image to expand the colour information to rgba:

for %%N in (D:\Karten\gdal\gdal2tiles\NL25\*.tif) DO gdal_translate -of vrt -expand rgba %%N D:\Karten\gdal\gdal2tiles\NL25\%%~nN.vrt

Second run, I merged all those vrts to a single one:

gdalbuildvrt -allow_projection_difference index25.vrt NL25\*.vrt

Maybe the command line arguments are limited in character size, which I got around by using the wildcards.


@AndreJ had the correct answer in their last statement.

It is a character limit. If you use the wildcard it runs fine. I just tried on 28000 tiffs and it ran no problem.

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