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I am using Normalize difference vegetation index (NDVI) derived from the landsat satellite band 3 and band 4 that have float values ranges from -1.0 to 1.0. I want to see the attribute table that is not possible in QGIS. I tried following expression in raster calculator of qgis but it did not work:

Int("float_raster" * 100)

the reason to multiply with 100 is to preserved the 2 digits at right level in attribute table that can be seen by again dividing by 100 in attribute table.

How can i scale see the better contrast in colour palette using qgis 2.40

marked as duplicate by whuber Jan 18 '17 at 21:33

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  • How exactly did this raster calculation "not work"? – whuber Feb 10 '15 at 21:37
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    @whuber. It executed successfully and added in TOC but I can not open the attribute table even. Only shift of 2 digits to left can be seen in the raster but not truncated (rounded) that should be in integer value conversion as does in arcGIS raster calculator. – Waseem Ali Feb 10 '15 at 21:46
  • Can you not then use Translate (GDAL_Translate) with an output type of 16 bit integer (-ot Int16) to perform the rounding of the results? – Michael Stimson Feb 10 '15 at 22:40
  • @MichaelMiles-Stimson. Can you please little bit explain how can i do it if this is the solution to cope with the problem. I do not know how to translate ... – Waseem Ali Feb 11 '15 at 12:39
  • I didn't know you could get an attribute table with rasters in QGIS. I'm also unclear on how converting from a float to a integer will resolve this problem. QGIS is more than capable of displaying Float values. Try this: qgistutorials.com/en/docs/raster_mosaicing_and_clipping.html – GIS-Jonathan Feb 11 '15 at 15:44
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I think this has been answered here How to round pixel values of a raster in QGIS?

Basically, QGis Raster Calculator does not do float <-> int conversion. Use gdal_translate instead.

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