Thanks a lot Marco! It's all much more clear to me now - specially after consulting your dissertation - it has a lot of valuable information for me. Very helpful share - thanks!
Paolo: I've followed your sugestion and opened a tickect suggesting a better documentation for the interpolation plugin --> https://trac.osgeo.org/qgis/ticket/3103 Best regards 2010/10/10 Marco Hugentobler <[email protected]> > 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 > [email protected] http://www.sourcepole.ch > Technical Advisor QGIS Project Steering Committee > _______________________________________________ > Qgis-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-user > -- --------------------------------------------------------------- Associação Leonel Trindade SOCIEDADE DE HISTÓRIA NATURAL Apartado 25 2564-909 Torres Vedras Portugal Sede e Biblioteca: rua Cavaleiros da Espora Dourada, 27A 2560 Torres Vedras Laboratório de Paleontologia e Paleoecologia: Polígono Industrial do Alto do Ameal 2565-641 Ramalhal http://alt-shn.blogspot.com www.alt-shn.org
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