Hi André > Now my question is: what does it mean the options "structured lines" and > "break lines"?
These options have no influence for IDW interpolation, only for TIN interpolation. -structure lines: triangle edges are constrained to line / polygon features (e.g. to prevent triangle edges crossing valleys, ridges or contours) -breaklines: like structure lines. But for cubic triangle interpolation ( clough-tocher), the break line is a edge (so not continuously differentiable) (details in http://www.geo.uzh.ch/fileadmin/files/content/abteilungen/gis/research/phd_theses/thesis_MarcoHugentobler_2004.pdf, chapter 5) >And by the way, > what does the "Distance coefficient" implies? It's the same parameter as the 'power' (IDW only has one parameter). Regards, Marco Am Samstag, 9. Oktober 2010, um 19.48:23 schrieb ALT SHN: > Hello List, > > I have a question about the QGIS Interpolartion Plugin. > > I have a line vector representing altitude by means of isolines of 10m, > covering an area of about 400 square km. I have read scientif paper that > advices the use of IDW with power 1-3 for hilly topography (thats my case). > > Now my question is: what does it mean the options "structured lines" and > "break lines"? How can they affect the accuracy of my DEM? And by the way, > what does the "Distance coefficient" implies? > > Thanks in advance > > André -- Dr. Marco Hugentobler Sourcepole - Linux & Open Source Solutions Webereistr. 66, CH-8134 Adliswil, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user