Frank,<br><br><div class="gmail_quote">On 15 April 2010 17:24, Frank Warmerdam <span dir="ltr"><<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div></div><div class="h5">Jose Gomez-Dans wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Basically, my raster looks like a black square with some "island blobs" where I have data. Some pixels in those blobs are flagged as unsuitable (using a mask band), and I would like to interpolate these unsuitable values. However, I want to make sure that the background NoData pixels in my original raster will be ignored.<br>
<br></blockquote></div></div>
Normally the raster fill algorithm uses the mask to identify pixels to<br>
be replaced, and it ignores the values of the pixels to be replaced. Often<br>
the pixels to replaced are all nodata and everything else is valid.<br>
<br>
As I understand, the region you want to replace is a subset of all the<br>
nodata pixels, but you still want to ensure that nodata pixels which<br>
are not being replaced are not included in the interpolation. Is that<br>
correct?<br></blockquote><div><br>What you say is mostly correct. A simpler way to explain it (I ought to have thought of that before!) is that if you use a external mask dataset, the raster fill algorithm should still honour ignoring the nodata values in the original dataset, as these data are meaningless. <br>
<br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I can't entirely follow how the patch will work but it seems to be<br>
doing essentially a reasonable thing. I am unfortunately hesitant to<br>
alter the GDALFillNodata() API at this point so I'm not sure your patch will<br>
make it back into the core. But once you have used it, I'd appreciate your<br>
submitting it as a ticket in case others need it.<font color="#888888"><br></font></blockquote><div><br>I'll try it and see how it goes. Thanks for your help!<br>Jose <br></div></div><br>