<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>
</div>
_______________________________________________
<br />
Qgis-user mailing list
<br />
<a
href="/user/SendEmail.jtp?type=node&node=5259726&i=0">[hidden
email]
<br />
List info: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
Unsubscribe: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a>
<br />
<br />
<hr noshade="noshade" size="1" />
<div style="color:#444;font:12px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif">
<div style="font-weight:bold">If you reply to this
email, your message will be added to the discussion
below:</div>
<a href="http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726.html">http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726.html</a>
</div>
<div style="color:#666;font:11px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif;margin-top:0.4em;line-height:1.5em">
To start a new topic under Quantum GIS - User, email <a href="http:///user/SendEmail.jtp?type=node&node=5259748&i=1">[hidden
email]</a> <br />
To unsubscribe from Quantum GIS - User, <a href="<a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node&%2361;4125267&code&%2361;bmljb2xhcy5jYWRpZXV4QGFyY2hlb3RlYy5jYXw0MTI1MjY3fDYzNDQ4MjQxNg&%2361;&%2361"><a class="moz-txt-link-freetext" href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro&#61;unsubscribe_by_code&amp;node&#61;4125267&amp;code&#61;bmljb2xhcy5jYWRpZXV4QGFyY2hlb3RlYy5jYXw0MTI1MjY3fDYzNDQ4MjQxNg&#61;&#61">http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=4125267&code=bmljb2xhcy5jYWRpZXV4QGFyY2hlb3RlYy5jYXw0MTI1MjY3fDYzNDQ4MjQxNg==</a>;">click
here.<br />
<a href="<a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id&%2361;instant_html%21nabble%3Aemail.naml&base&%2361;nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs&%2361;notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml">http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml</a>"
style="font:9px serif">NAML </div>
</blockquote>
</div>
<br />
<hr width="300" align="left" />
View this message in context: <a href="http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726p5259730.html">Re: no data
in raster calculator NDVI</a><br />
Sent from the <a href="http://osgeo-org.1560.x6.nabble.com/Quantum-GIS-User-f4125267.html">Quantum GIS
- User mailing list archive</a> at Nabble.com.<br />
<br />
_______________________________________________<br />
Qgis-user mailing list<br />
<a href="http:///user/SendEmail.jtp?type=node&node=5259748&i=2">[hidden
email]</a><br />
List info: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
Unsubscribe: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
</blockquote>
</div>
<br />
</div>
<br />
_______________________________________________
<br />
Qgis-user mailing list
<br />
<a href="http:///user/SendEmail.jtp?type=node&node=5259748&i=3">[hidden email]</a>
<br />
List info: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
Unsubscribe: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a>
<br />
<br />
<hr noshade="noshade" size="1" />
<div style="color:#444;font:12px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif">
<div style="font-weight:bold">If you reply to this email, your
message will be added to the discussion below:</div>
<a href="http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726p5259748.html">http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726p5259748.html</a>
</div>
<div style="color:#666;font:11px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif;margin-top:0.4em;line-height:1.5em">
To start a new topic under Quantum GIS - User, email
<a href="http:///user/SendEmail.jtp?type=node&node=5259755&i=0">[hidden email]</a> <br />
To unsubscribe from Quantum GIS - User, click
here.<br />
<a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" style="font:9px serif">NAML</a> </div>
</blockquote><div><div>
<br />
<br /><hr align="left" width="300" />
View this message in context: <a href="http://osgeo-org.1560.x6.nabble.com/no-data-in-raster-calculator-NDVI-tp5259726p5259755.html">Re: no data in raster calculator NDVI</a><br />
Sent from the <a href="http://osgeo-org.1560.x6.nabble.com/Quantum-GIS-User-f4125267.html">Quantum GIS - User mailing list archive</a> at Nabble.com.<br /></div></div><br />_______________________________________________<br />
Qgis-user mailing list<br />
<a href="mailto:Qgis-user@lists.osgeo.org">Qgis-user@lists.osgeo.org</a><br />
List info: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
Unsubscribe: <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br /></blockquote></div><br /></div>
</blockquote></div>