Hi everybody, and thanks for the good ideas.
I've finally managed to create what seems to be a good solution for
creating a coverage area around a point dataset, and I thought I
might inform you, in case somebody else has a similar challenge.
A small resume first: I have a bunch of text files (simple format
with xyz columns), each with a cloud of DEM points from a laser scan,
and I wanted to create a polygon that represents the complete area
covered by the scan. Mark suggested that I could use ConvexHull, but
unfortunately the resulting polygons were a bit to generalized.
My basic idea was to convert each DEM file to a raster, reclassify
the raster to 1 (inside) and Nodata (outside), and finally convert
the raster to polygon features. But I couldn't find any FME
transformer for converting from raster to feature, so I had to
combine FME and ArcGIS.
To be able do this in batch, I created a workspace where each of the
DEM-files is converted from the text format to a raster (ESRI ASCII
GRID). After the raster creation, a python script is run ("Shutdown
python script" in FME), where ArcGIS tools are used to convert the
raster to polygon features and add them to a Shape file.
I then created a batch deploy of the workspace, with all my DEM point
files. The result was a Shape file with a good representation of the
complete coverage area.
Regards, Knut Jetlund
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