<div dir="ltr">Hi <br><br>I'm new to the world of geotiff and I'm running<br>into a problem when generating small area coverage<br>geotiffs<br><br>I'm collecting images using a robotic submarine (an AUV)<br>and want to use geotiff to locate these images for use in a<br>
GIS etc. Typical footprint for the images is 1m x 1.5m<br><br>If I write the geotiff tags using the correct size then the<br>image appears badly distorted when viewed in openev and<br>in arcgis. If however I keep everything else the same and <br>
pretend that the image is 1Km x 1.5Km the image will appear<br>undistorted.<br><br>Has anyone come across this issue before, is there some fundamental<br>lower limit on the image size that I've not picked up on? Or can someone<br>
tell me how to search the mailing list archives for similar issues?<br><br>Example images are available at.<br>
<a href="http://www-personal.acfr.usyd.edu.au/d.mercer/geotiff">http://www-personal.acfr.usyd.edu.au/d.mercer/geotiff</a><br>
Large image appears ok, but oversized. Small image is distorted<br>
(at least in openev. I haven't been able to check this one in arcgis<br>but I have seen the issue with other images I have generated in the past)<br>
<br>
<br><br><br>FYI.<br>I am using libgeotiff and writing the following geotags...<br><br> TIFFSetField(tif_ptr, TIFFTAG_GEOTRANSMATRIX, 16, position.transform); <br><br> GTIFKeySet(gtif_ptr, GTModelTypeGeoKey, TYPE_SHORT, 1, ModelTypeProjected);<br>
GTIFKeySet(gtif_ptr, GTRasterTypeGeoKey, TYPE_SHORT, 1, RasterPixelIsArea);<br> <br> GTIFKeySet(gtif_ptr, ProjectedCSTypeGeoKey, TYPE_SHORT, 1, utm_zone);<br> GTIFKeySet(gtif_ptr, PCSCitationGeoKey, TYPE_ASCII, PCS_Zone.str().length(), PCS_Zone.str().c_str());<br>
<br><br>Any help or suggestions gratefully received.<br>Best regards<br>Duncan<br><br><br>-- <br>Dr Duncan Mercer<br>Australian Centre for Field Robotics<br>The Rose Street Building, J04<br>The University of Sydney.<br>2006 NSW, Australia<br>
Tel: +61 (0) 2 9036 7178<br>Fax: +61 (0) 2 9351 7474
</div>