<html><body><div style="color:#000; background-color:#fff; font-family:tahoma, new york, times, serif;font-size:10pt"><div>Hi,</div><div><br></div><div>I have 10k small polygons stored in a shapefile and in raster format (nr classes = nr of basins). </div><div>I am interested in getting some planar geometry information for each polygon.</div><div>I have 3 problems, not considering the lack of knowledge: </div><div><br></div><div>- no DTM; </div><div>- no channels; </div><div>- try to foul r.basin with the shapefile</div><div><br></div><div><span style="font-size: 10pt; ">Can you think of a way to pick the module and its code to calculate the indices in the end of the post? </span></div><div><span style="font-size: 10pt; ">Can anyone point me a way to pick up the major axis instead of the lenght of the main channel ? </span></div><div><span style="font-size: 10pt; ">Any hint on major (or minor) axis
extraction?</span></div><div><br></div><div>Should I try other approach? </div><div><br></div><div>Thanks in advance</div><div>Marco</div><div><br></div><div><br></div><div>"</div><div><ul style="line-height: 19px; list-style-type: square; margin: 0.3em 0px 0px 1.5em; padding: 0px; list-style-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAANCAMAAABW4lS6AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAAZQTFRFAFKM////QIUK9QAAAAJ0Uk5T/wDltzBKAAAAGklEQVR42mJgBAEGokgGBjBGBxBxsBqAAAMACHwALd5r8ygAAAAASUVORK5CYII=); font-family: sans-serif; "><li style="margin-bottom: 0.1em; "><span style="font-style: italic;">The <b>circularity ratio</b>: is the ratio between the area of the basin and the area of the circle having the same perimeter of the basin.</span></li><li style="margin-bottom: 0.1em; "><span style="font-style: italic;">The <b>elongation ratio</b>: is the ratio between the diameter of the circle having the same area of
the basin and the length of the main channel.</span></li><li style="margin-bottom: 0.1em; "><span style="font-style: italic;">The <b>compactness coefficient</b>: is the ratio between the perimeter of the basin and the diameter of the circle having the same area of the basin.</span></li><li style="margin-bottom: 0.1em; "><span style="font-style: italic;">The <b>shape factor</b>: is the ratio between the area of the basin and the square of the length of the main channel</span></li></ul><div><span>"</span></div></div></div></body></html>