<p dir="ltr">Hi,</p>
<p dir="ltr">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.</p>
<p dir="ltr">Nicolas</p>
<div class="gmail_quote">On Apr 7, 2016 13:08, Mariana Buzzi <marianabuzzi86@gmail.com> wrote:<br type='attribution'><blockquote class="quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi!!!<div>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.</div><div>Thanks!!!</div><div><br /></div><div>Regards,</div><div>Mariana</div></div><div><br /><div class="elided-text">2016-04-05 12:10 GMT-03:00 Nicolas Cadieux <span dir="ltr"><<a href="mailto:nicolas.cadieux@archeotec.ca">nicolas.cadieux@archeotec.ca</a>></span>:<br /><blockquote style="margin:0 0 0 0.8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  
    Hi Marina,<br />
    Please post more information on the exact calculation you are using.
    This could help:
<a href="http://gis.stackexchange.com/questions/103122/how-to-generate-a-ndvi-in-qgis">http://gis.stackexchange.com/questions/103122/how-to-generate-a-ndvi-in-qgis</a><br />
    Nicolas<br />
    <br />
    <div>Le 2016-04-05 10:34, Mariana Buzzi-2
      [via OSGeo.org] a écrit :<br />
    </div>
    <blockquote style="border-left:2px solid #cccccc;padding:0 1em">
      <div dir="ltr">Thanks Nicolas!
        <div>But...I check the CSR and It is right. I didn´t work with
          more than one layer...</div>
        <div>Any idea please!???</div>
        <div><br />
        </div>
        <div>Regards,</div>
        <div>Mariana</div>
      </div>
      <div><br />
        <div class="elided-text">2016-04-05 10:20 GMT-03:00 Nicolas
          Cadieux <span dir="ltr"><<a href="http:///user/SendEmail.jtp?type=node&node=5259748&i=0">[hidden
              email]</a>></span>:<br />
          <blockquote style="border-left:2px solid #cccccc;padding:0 1em">
            <p dir="ltr">Hi,</p>
            <p dir="ltr">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... </p>
            <p dir="ltr"> You are using more than one layer?  Maybe add
              information  on what exactly you are doing. That would
              help others help you.<br />
              Cheers!</p>
            <p dir="ltr">Nicolas<br />
            </p>
            <p dir="ltr">Nicolas</p>
            <div class="elided-text">
              <div>
                <div>On Apr 5, 2016 08:45, "Mariana Buzzi-2
                  [via OSGeo.org] " <<a href="http:///user/SendEmail.jtp?type=node&node=5259730&i=0">[hidden
                    email]</a>> wrote:<br />
                </div>
              </div>
              <blockquote style="border-left:2px solid #cccccc;padding:0 1em">
                <div>
                  <div>
                    <div dir="ltr">Hi everybody!!!!
                      <div><br />
                      </div>
                      <div>
                        <div>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?</div>
                        <div>Thank you so much!!!!</div>
                        <div><br />
                        </div>
                        <div>Regards,</div>
                        <div>Mariana</div>
                      </div>
                      <div><br />
                      </div>
                    </div>
                    <br />
                  </div>
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