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<div><span>So there is no way of changing the nearest-neighbour resampling in d.rast to lanczos for example?</span></div><div><span><br></span></div><div><span><blockquote type="cite" style="border-left-style: solid; border-left-color: rgb(204, 204, 204); border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; margin-left: 0px; padding-left: 10px; padding-right: 0px; margin-right: 0px; "><span><div><div>If you want optimal output, the display size needs to match the<br>current region,</div></div></span></blockquote>
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<span><div><span>How do I adjust the current region to match the display size? Region works with rows and columns, so what is the connection to my display pixels?</span></div><div><span><br></span></div><div><span><blockquote type="cite" style="border-left-style: solid; border-left-color: rgb(204, 204, 204); border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; margin-left: 0px; padding-left: 10px; padding-right: 0px; margin-right: 0px; "><span><div><div>Either that, or render the map at its native resolution, then resample<br>using an image-processing program.</div></div></span></blockquote></span></div><div><span>This is not an option, because I need the 'prettier' image inside GRASS to vectorize some features.</span></div><div><span><br></span></div><div><span><br></span></div><div><span>Thank you,</span></div><br>-- <br>Sebastian Beyer<br><br></span>
<p style="color: #a0a0a0;">On Friday, July 8, 2011 at 6:00 AM, Glynn Clements wrote:</p>
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<span><div><div><br>sleepysebi wrote:<br><br><blockquote type="cite"><div>since April I'm working with GRASS and I think by now I got the basics.<br>Now I'm working with high resolution satellite data, looking for small<br>structures in ice.<br>My Rasterimages have got a resolution up to 2.5 meters per pixel, but most<br>of the time<br>I don't zoom in that far.<br>So the Problem is, when zoomed out GRASS doesn't displays the raster the way<br>I want it to.<br>To me it seems that it's a problem with resampling the image when<br>displaying, but I'm not shure if I'm missing something.<br>To make it clear I made a little screenshot:<br><br><a href="http://imageshack.us/f/225/resamplecomparison.png/">http://imageshack.us/f/225/resamplecomparison.png/</a><br><br>So when at the same zoom lvl in EOG, it does some kind of 'smoothing' which<br>looks way better.<br><br>I know I can use *r.resamp.interp to resample, using lanczos for example,<br>but this is more for the final output, not for working inside GRASS<br>(vectorizing,...).<br></div></blockquote><br>The GRASS library resamples all input maps to the current region using<br>nearest-neighbour resampling. d.rast then resamples the data to the<br>display (image or window) size, again using nearest-neighbour<br>resampling.<br><br>If you want optimal output, the display size needs to match the<br>current region, and the input map needs to be explicitly resampled to<br>the current region using e.g. r.resamp.interp or r.resamp.filter.<br><br>Either that, or render the map at its native resolution, then resample<br>using an image-processing program.<br><br>-- <br>Glynn Clements <<a href="mailto:glynn@gclements.plus.com">glynn@gclements.plus.com</a>><br></div></div></span>
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