Fran�ois Bergeron wrote: > Does someone know the algorithm (formula) Vertical Mapper uses to calculate the >slope function?
The "unofficial" explanation (from a while ago) is this: >> "We calculate slope the same way everyone else does. Rise over Run. What people >don't realize is that calculating the slope of a grid cell is not that simple. The >slope of the cell depends on the cells around it. It is possible to draw 8 triangles >between the centre of a particular cell, and the centres of the cells surrounding it. > We calculate the slope by figuring out the slope of each of these eight triangles, >and then averaging the result. From what I've read of ArcView, it simply gives you >the Maximum slope found, which may or may not be what the users want. We'll be >adding this ability in the next version so that users can find the maximum slope, or >the minimum slope, or keep getting the average slope. >> >> What people tend to forget, is that if you're walking up a 45 degree slope, yes, >the slope up and down is 45 degrees, but the slope side to side won't be 45 degrees. >It will be something slightly less." -- - Bill Thoen ------------------------------------------------------------ GISnet, 1401 Walnut St., Suite C, Boulder, CO 80302 tel: 303-786-9961, fax: 303-443-4856 mailto:[EMAIL PROTECTED], http://www.gisnet.com ------------------------------------------------------------ _______________________________________________________________________ List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MapInfo-L" in the message body.
