Hi Knut, if you have grid values as easy as 1 for inside and 0 for outside you could try to create contours at level 0.5.
Kind regards, Wolfgang Rieger --- In [email protected], "kjetlund" <[EMAIL PROTECTED]> wrote: > > > Hi Mark, and thanks for your quick reply. > > The ConvexHull solution sounded to me like a a good idea, but > unfortenatly, the polygons that are created are to simple for this > purpose. Some important breakpoints are excluded. An area that should > have become like a fat "L" become more like a triangle. Is there > something I could do to avvoid this? > > I have been working on a alternate solution in ArcGIS where i convert > the points to a raster, reclassify all values that are not nodata to > "1", and convert the raster to polygons. The resulting polygons are > close to what I want, except that there are some small donuts inside > them. I would, of severeal reasons, like to use FME instead of ArcGIS , > but I can't find a transformer that create polygons from raster. Does > it excist? > > Regards, Knut Jetlund > > > --- In [email protected], "mark2atsafe" <mark.ireland@> wrote: > > > > I think ConvexHullReplacer/Accumulator is what you need. > > > > Regards, > > > > Mark > > > > Mark Ireland, Senior Product Specialist > > Safe Software Inc. Surrey, BC, CANADA > > support@ http://www.safe.com > > Solutions for Spatial Data Translation, Distribution and Access > > > > --- In [email protected], "kjetlund" knut.jetlund@ wrote: > > > > > > Hi all > > > > > > I have a large amount of DEM points from a laser scan, which cover > > > part of an area where I need to create a surface model. When > creating > > > the model, I want to combine the points with contour lines and other > > > elevation data. The laser data is much more accurate than the > contour > > > lines, and because of this, I want to use only the DEM points inside > > > the coverage area of the laser scan. > > > > > > In other words, I need to clip the contour lines (and some other > data) > > > against the coverage area of the laser scan. But my problem is that > I > > > don't have a polygon of the coverage area, I just have the points. > > > > > > Is there a simple way of creating this area? It's not rectangular, > so > > > I can't use a Bounding Box. I can create a small buffer around each > > > point, and dissolve to one large area. But I think this would become > > > a very heavy operation for my computer, given the number of points. > > > Perhaps it would be better to create two surface models, and in some > > > way run a overlay between them? > > > > > > Any suggestions? > > > > > > Regards, > > > Knut Jetlund > > > Norwegian Public Roads Administration > > > > > > For insights into what's up at Safe Software and what's on the development horizon, visit Safe's blog at spatial-etl.blogspot.com. Love FME? Then open your diary to March 6-7, 2008 and write this... "Second Worldwide FME User Conference - Must Attend!" See http://www.safe.com/company/fmeuc2008/index.php for more details. Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/fme/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/fme/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
