IN FME workbench 2016.1 I want to create a DEM from Multipatch-geometry contained in a geodatabase, for doing that I thought using the SurfaceModeller could work, where in SurfaceModeller I group the points by the UUID generated attribute: enter image description here

But the errors are

The specified cell size of '2' units in the y axis is invalid. Cell size must be less than raster extents

Surface Model cannot be constructed. Either all points are linear or initial set of points did not consist of 3 non NAN elevations

For the first error I think it's due to objects with 3 points in less than a diameter of 2 meters Second error is due to objects with less than 3 points Questions: 1) how could I exclude/drop/ignore geometries with less than 3 points ? 2)how could I still add a cell value to objects less than 2 m ?


I wonder what coordinate system you are using? Basically the "cell size" error is because you are asking for a DEM spacing that's greater than the source dataset itself; for example I have a raster file 500m x 500m and ask for a DEM grid of 1000m.

The DEM grid uses the units of the source data, which means that if you were using Lat-Long data, then a cell size of 2 would mean 2 degrees, which is likely larger than the source data itself.

If your data is in degrees, but you want feet/metre units for the grid instead, then use a Reprojector to reproject the data. You could also specify the DEM spacing in decimal degrees, but I don't know that I'd recommend that.

I do notice you have a CoordinateSystemSetter. Be aware that it does not reproject data, it just tags the data with a specified coordinate system (i.e. the reader doesn't know the coordinate system, so this is you telling FME what it is). Again, use the Reprojector transformer if you want to reproject data.

This could also be the cause of the second error, or the second error is a result of the first. I suggest fixing the first error, then posting the second - if it still exists - as a separate question (otherwise you're likely to have the question closed as being too broad!)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.