Hi,

 

If you find it easy to use GDAL, you can use the SystemCaller transformer (in combination with  a StringConcatenator ) to execute the GDAL command(s).

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Hi,

 

 

you're right, the RasterExpressionEvaluator could do this. Have you looked at the FMEpedia articles for this transformer?

 

 

http://fmepedia.safe.com/articles/Samples_and_Demos/Examples-using-the-RasterExpressionEvaluator-Transformer

 

 

http://fmepedia.safe.com/articles/Samples_and_Demos/Using-Conditions-with-the-RasterExpressionEvaluator-Transformer

 

 

David

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Hi Itay and David,

 

 

Thank you for your answers!

 

Itay: Yes I know about the SystemCaller but in this case I'm trying to use FME without any other programs involved.

 

David: Yes I have already seen the FMEPedia articles (good examples).

 

 

I can solve it with the RasterExpressionEvaluator but the expression becomes a little complicated. The color ramp in my example will have this expression (if I'm correct):

 

 

if(A[0]<5,((5-A[0])/5)*(255-225) + 225,

 

  if(A[0]>=5 && A[0]<10,((5-A[0])/5)*(225-205) + 205,

 

  if(A[0]>=10 && A[0]<15,((5-A[0])/5)*(205-190) + 190,

 

   if(A[0]>=15 && A[0]<20,((5-A[0])/5)*(190-178) + 178,

 

    if(A[0]>=20 && A[0]<25,((5-A[0])/5)*(178-166) + 166,

 

     if(A[0]>=25 && A[0]<30,((5-A[0])/5)*(166-154) + 154, 

 

      if(A[0]>=30 && A[0]<35,((5-A[0])/5)*(154-142) + 142, 

 

       if(A[0]>=35 && A[0]<40,((5-A[0])/5)*(142-130) + 130, ((90-A[0])/50)*130))))))))

 

 

The result:

 

Before:

 

 

 

After:

 

 

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U can extract the colormap and built a new one..

 

 

Then u can do the testing and mapping using ie rangemappng. I think it does look better then the expressions in the rasterexpressionevaluater.

 

 

the drawback is that this takes a lot of transformers to accomplish...wel at least in my workspace. A workspace that makes density maps to see wether busstops "reach" people and dont make walk them to much.... i just counted: 14 transformers (including mapping) to get it done.

 

Then reattaching the new map to the raster, another 2 transformers.

 

 

....hhmmmm

 

 

I did redo it using a tcl caller. A small tcl script in 1 transformer.

 

Still, the mapping needs to be done.

 

But looks way better.

 

 

Is using tcl also out of the question? Else i'd go for that (or Python)

 

 

Gio

 

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As a side note: there is a feature enhancement request at Safe to implement raster support to the fmeobjects Python API. I think this is another good use case for it.

 

 

Consider asking Safe to implement these raster classes so that we can do this kind of operations in a PythonCaller rather then messing about with so many transformers :-)

 

 

The more who request a feature, the more likely it is to be implemented...

 

 

David

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