Hi,
Not sure. I would help if you cut and paste the exact formula you are using in the raster calculator. Perhaps you are dividing by zeros? If zero is the no data value then that could be the problem. There could be a confusion between the value zero and the no data value. If your values are very small, try multiplying a raster by a large number like a million. You could send a small sample of your files along with the results. We could perhaps have a look.
Nicolas
On Apr 7, 2016 13:08, Mariana Buzzi <[email protected]> wrote:
Hi!!!I am working with SPOT 5 image. First I transforme the image with TOA plugin, and with datas I did the NDVI.To perform the calculation of NDVI I use the raster calculator. In QGIS v. 2.8.3. From the Raster tool -> Raster calculator. And there select the appropriate bands for the calculation (NIR-R / NIR + R). The output file generated is a geotiff, which has a large number of pixels no data (no data). Therefore I would like to know why this occurs and how I can do about it.Thanks!!!Regards,Mariana2016-04-05 12:10 GMT-03:00 Nicolas Cadieux <[email protected]>:Hi Marina,
Please post more information on the exact calculation you are using. This could help: http://gis.stackexchange.com/questions/103122/how-to-generate-a-ndvi-in-qgis
Nicolas
Le 2016-04-05 10:34, Mariana Buzzi-2 [via OSGeo.org] a écrit :
Thanks Nicolas!But...I check the CSR and It is right. I didn´t work with more than one layer...Any idea please!???
Regards,Mariana
2016-04-05 10:20 GMT-03:00 Nicolas Cadieux <[hidden email]>:
Hi,
I don't use NDVI raster calculation but if you have no data values where you thinks you have some data, then my first reaction would be to see if all the layers are in the same CRS in case the plugin does not reprojection on the fly...
You are using more than one layer? Maybe add information on what exactly you are doing. That would help others help you.
Cheers!Nicolas
Nicolas
On Apr 5, 2016 08:45, "Mariana Buzzi-2 [via OSGeo.org] " <[hidden email]> wrote:
_______________________________________________Hi everybody!!!!
I'm doing a calculation with NDVI raster calculator. When I generate the calculation results I get a lot of pixels without values (no data). How I can do to fill those values with data?Thank you so much!!!!
Regards,Mariana
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