[gdal-dev] Limit on the number of files for gdalbuildvrt

[Even Rouault]

On mercredi 30 octobre 2019 15:52:54 CET Jose Gomez-Dans wrote:
> Hi,
> 
> I'm mosaicking a large number of small tiles using the GDAL python bindings
> (python 3.7, gdal 3.0.1, but also tested on 2.4.2). Code is something like
> 
> ```
> 
> *output_fname = "/something/or/other.vrt"*
> *fnames = ["file1.tif", ..., "fileN.tif"]*
> 
> 
> 
> 
> *dst_ds = gdal.BuildVRT(            output_fname,            fnames,
>     options=gdal.BuildVRTOptions(separate=True),        )*
> *dst_ds = None*
> ```
> 
> This fails with lots of errors like
> ERROR 4: fileXXX.tif: No such file or directory
> Warning 1: Can't open fileXXX.tif. Skipping it

gdalbuildvrt is normally cautious about non opening too many files at the same 
time. I can't replicate your issue with the following script

```
from osgeo import gdal
import shutil

fnames = []
for i in range(1024):
    dstname = 'testbuildvrt/byte%d.tif' % i
    shutil.copy('byte.tif', dstname)
    fnames.append(dstname)

dst_ds = gdal.BuildVRT(
            "/tmp/out.vrt",
            fnames,
            options=gdal.BuildVRTOptions(separate=True),
        )
dst_ds = None
```

> The aim of this is to create a VRT mosaic that can then be converted to
> GeoTIFF.

If you want a mosaic, you likely want separate=False.

Even

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