Patrice, Daniel,<br><br><br>Thank you for your commments - it shaded some light on the subject.<br><br>Regards,<br><br>André Mano<br><br><div class="gmail_quote">2012/2/5 Patrice Dumas <span dir="ltr"><<a href="mailto:pertusus@free.fr">pertusus@free.fr</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Sun, Feb 05, 2012 at 07:22:29AM -0200, Daniel Victoria wrote:<br>
> Hi Andre,<br>
><br>
> On raster algebra, operations using null will return null while operations<br>
> with 0 behaves like expected. Ex:<br>
> 12 x null = null<br>
> 12 x 0 = 0<br>
<br>
</div>Also means do not behave the same on NULL, for example when using r.univar<br>
(according to my understanding of the documentation, haven't tested)<br>
NULL cells are excluded from the computation, so 1 cell with a value 1<br>
and 9 NULL will give a mean of 1 while 1 cell with a value 1 and 9 with<br>
value 0 will give a mean of 0.1.<br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Pat<br>
</font></span><div class="HOEnZb"><div class="h5">_______________________________________________<br>
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