gdal_translate with stats and a_nodata

[Mike Taves]

I have a gridded XYZ file that I'd like to translate to a GeoTIFF with NODATA and with statistics. Here an example source file myraster.xyz:

X Y Z
0 0 -999
1 0 10
0 1 15
1 1 20

So the command line is:

$ gdal_translate -a_nodata -999 -stats myraster.xyz  myraster.tif

however from gdalinfo myraster.tif

Band 1 Block=2x2 Type=Int16, ColorInterp=Gray
  Min=-999.000 Max=20.000
  Minimum=-999.000, Maximum=20.000, Mean=-238.500, StdDev=439.089
  NoData Value=-999
  Metadata:
    STATISTICS_MAXIMUM=20
    STATISTICS_MEAN=-238.5
    STATISTICS_MINIMUM=-999
    STATISTICS_STDDEV=439.08911396207

How can the minimum value be the same as the NODATA? It's illogical.

It appears that -stats was applied to myraster.xyz which does not yet have a NODATA, since I see a new file myraster.xyz.aux.xml with the same statistics without consideration of the NODATA.

---

One workaround is to set NODATA unintuitively in myraster.xyz.aux.xml:

<PAMDataset>
  <PAMRasterBand band="1">
    <NoDataValue>-9.99000000000000E+002</NoDataValue>
  </PAMRasterBand>
</PAMDataset>

where the same translation results with expected results:

Band 1 Block=2x2 Type=Int16, ColorInterp=Gray
  Min=10.000 Max=20.000
  Minimum=10.000, Maximum=20.000, Mean=15.000, StdDev=4.082
  NoData Value=-999
  Metadata:
    STATISTICS_MAXIMUM=20
    STATISTICS_MEAN=15
    STATISTICS_MINIMUM=10
    STATISTICS_STDDEV=4.0824829046386

[Even Rouault]

trunk r27298, branches/1.11 r27299 "VRT: make sure nodata value set on VRT raster band is taken into account in statistics computation (#5463)"

[Even Rouault]

Test added in r27300