Hello, I cannot really answer your question, but I have been working with a combination of your fuzzy modules for GRASS and r.param.scale in order to accomplish a fuzzified version of Wood's morphometric feature extraction method.
In doing so, I noticed that the results of "r.param.scale param=feature" differ very much from the results of this same module in Wood's original software Landserf, by using the same slope and curvature thresholds. Do you think this can be an associated issue to what you mentioned? All I can say is that the formula you described (the one used in GRASS) is exactly the same that is in Wood's Ph.D. thesis, which in turn is based in Evans (1979) work, as you probably already know. By the way, great fuzzy modules! Best regards, Marcello. Jarek Jasiewicz wrote: > > Hi > while I modified r.param.scale for my purposes I noticed that some > formulas for curvatures differs from that I know: > > > for example: > > plan curvature: is > > (2.0 * (b * d * d + a * e * e - c * d * e) / > pow(e * e + d * d, 1.5)); > > probably shall be: > > ( (b * d * d + a * e * e - 2.0 *(c * d * e)) / > pow(e * e + d * d, 1.5)); > > > profile curvature: is > > return (-2.0 * (a * d * d + b * e * e + c * e * d) / > ((e * e + d * d) * pow(1.0 + d * d + e * e, 1.5))); > > probably shall be: > > return (- (a * d * d + b * e * e + 2.0* (c * e * d)) / > ((e * e + d * d) * pow(1.0 + d * d + e * e, 1.5))); > > Of course threre could be reasons why little different formulas are used > but I do not see any. > > This formulas is in grass 6.4, 6.5 and 7.0 and I assume in older version > too. > > regards > Jarek > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > > -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/r-param-scale-curvatures-are-really-OK-tp5696388p5698886.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user