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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi List,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a technical question regarding the workings of ‘ogr2ogr –spat’<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>From the description regarding this option is:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-AU'>-spat</span></b><i><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-AU'> xmin ymin xmax ymax</span></i><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-AU'>:<o:p></o:p></span></p><p class=MsoNormal style='margin-left:36.0pt'><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-AU'>spatial query extents. Only features whose geometry intersects the extents will be selected. The geometries will not be clipped unless -clipsrc is specified <o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>This can be found at the following website: <a href="http://www.gdal.org/ogr2ogr.html"><span style='color:windowtext;text-decoration:none'>http://www.gdal.org/ogr2ogr.html</span></a> This provides more information than the command line help.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My question is what does the sentence ‘Only features whose geometry intersects the extents will be selected’ actually mean? What type of intersection is implied?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a spatial data source which I will describe in a generalized fashion as a set of polygons and disjoint multi-polygons that are arranged like 4 concentric rings. The rings themselves are not polygons or multi-polygons but rather groups of them compose each ring. Label the rings from 1 to 4; the inner smallest circle is 1; the largest outer ring is 4.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>I want to extract from the spatial data source only those geometries that have some part of them within a rectangular extent (spat extent) that covers, in some part, rings 1, 2 and 3 but not ring 4. When I use org2org –spat with the required extent I am getting geometries from ring 4. These geometries are disjoin multi-polygons that exist, in parts, around the whole of ring 4 but no part of the actual geometries extend into the rectangular extent, only the minimal bounding box of the geometry which of course covers the whole of the rectangular extent.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Is the implied intersection related to the minimal bounding box of the geometries and the rectangular extent?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>How would I use the various options to achieve what I need?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sorry if the description is vague. I could have described the spatial data source too generally and therefore misconstrued the problem entirely. I could provide a picture of the spatial representation of the data source showing the problem if people find it beneficial.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks in advance,<o:p></o:p></p><p class=MsoNormal>Brett<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>Brett Walker</b> <<a href="mailto:brett.walker@geometryit.com"><span style='color:blue'>brett.walker@geometryit.com</span></a>><o:p></o:p></p><p class=MsoNormal>Software Developer / Analyst<o:p></o:p></p><p class=MsoNormal>Geometry Pty Ltd<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:9.0pt'>Telephone 03 6223 1999<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt'>Mobile 0458 498 386<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt'>Fax 03 6223 1988<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt'>Web <a href="http://www.geometryit.com/"><span style='color:blue'>www.geometryit.com</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt'>Address 31 Salamanca Square, Battery Point, TAS 7004, Australia<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>