Question

data from raster in a polygon


Hello,

I'm new in FME and I want to put, in a polygon, the minimum value (from a raster) in this polygon inside this polygon.

 

 

 

 

I use :

"RasterToPolygonCoercer" to extract data,

"AreaOnAreaOverlayer" to transfert data to polygon.

But I cannot think how to do this.


4 replies

Userlevel 1
Badge +10

Have you tried clipping the raster with the polygon, then using a rasterstatistics calculator on the resulting clipped raster to get the minimum?

Badge +22

@ebygomm has the right approach. You want to have a unique id on the polygons, if they don't already have one, you can use a Counter to create one. On the clipper, merge attributes. After the RasterStatisticsCalculator use a FeatureMerger/FeatureJoiner to join the band0.min value back to the original polygons based on the unique id.

Userlevel 1
Badge +10

@ebygomm has the right approach. You want to have a unique id on the polygons, if they don't already have one, you can use a Counter to create one. On the clipper, merge attributes. After the RasterStatisticsCalculator use a FeatureMerger/FeatureJoiner to join the band0.min value back to the original polygons based on the unique id.

I normally store the geomety as an attribute with a geometryextractor then rebuild after with a geometryreplacer. Feels a bit neater than the featuremerger.

Badge +22

I normally store the geomety as an attribute with a geometryextractor then rebuild after with a geometryreplacer. Feels a bit neater than the featuremerger.

That's an idea. I will need to do some performance tests to see which scenarios are better for which approach.

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