<html>
<head>
<style>
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Verdana
}
</style>
</head>
<body class='hmmessage'>
Thanks for the reply. I do not see how anti-aliasing techniques could be used here. <br><br>Does anyone else have simple answers to the two elementary questions?<br><br>Thanks a lot in advance.<br> <br>With best regards.<br>~Belaid.<br><br>> Date: Sat, 12 Sep 2009 16:24:54 +0530<br>> Subject: Re: [gdal-dev] pixel/line mapping for two images.<br>> From: chaitanya.ch@gmail.com<br>> To: belaid_moa@hotmail.com<br>> CC: gdal-dev@lists.osgeo.org<br>> <br>> Belaid,<br>> <br>> GDAL uses various interpolation/resampling algorithms like nearest<br>> neighbour, bilinear, cubic, cubic spline and lanczos. However, I think<br>> these may not be what you are looking for.<br>> <br>> Computing the overlap of pixels of two images should not be a complex<br>> process. You may find some ideas with anti-aliasing techniques.<br>> <br>> On Sat, Sep 12, 2009 at 12:36 PM, Belaid MOA <belaid_moa@hotmail.com> wrote:<br>> > Hi everyone,<br>> > I have two elementary questions about how GDAL maps the pixel/line of one<br>> > image to an other image.<br>> > Suppose we have two GeoTiff images with different spatial resolutions and<br>> > projections.<br>> > According to GDAL code, a pixel/line (i,j), more precisely its center<br>> > (i+0.5,j+0.5), of the first image is mapped to the pixel/line (p,q) of the<br>> > second image, where p and q are doubles that usually have fraction parts.<br>> > My questions are: what is the meaning for these fractions? Is it possible to<br>> > use these fractions to compute the overlap between<br>> > the pixels of the two images using GDAL?<br>> ><br>> > Any help on this is very appreciated!<br>> > Thank you very much in advance.<br>> ><br>> > ~Belaid.<br>> ><br>> ><br>> ><br>> ><br>> > ________________________________<br>> > Less clicking: Hotmail access on the new MSN homepage.<br>> > _______________________________________________<br>> > gdal-dev mailing list<br>> > gdal-dev@lists.osgeo.org<br>> > http://lists.osgeo.org/mailman/listinfo/gdal-dev<br>> ><br>> <br>> <br>> <br>> -- <br>> Best regards,<br>> Chaitanya kumar CH.<br><br /><hr />Less clicking: Hotmail access on the new <a href='http://go.microsoft.com/?linkid=9677398' target='_new'>MSN homepage.</a></body>
</html>