Question

Classify raster data by breakpoints

  • 18 October 2016
  • 4 replies
  • 27 views

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Hello FME-Community,

 

 

I’d like to classify raster data by using breakpoints and I want to adapt the RGB-Codes before the output. Maybe someone of the community here can help me.

 

 

Thank you so much. :)

 

 

Best regards!


4 replies

Badge +16

Hi @abu_de_bdlq_16 I think this article is a good starting point on how to use the RasterExpressionEvaluator to classify your rasters.

It would help if you could specify more on what you are actually trying to achieve.

Badge +22

You can use conditional values in a RasterExpressionEvaluator, but nesting several layers makes the expression very complicated.

 

 

Depending on your exact scenario, I might recommend using the RasterCellValueReplacer and paletes.
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Both ways are possible, thank you so much. :)

Userlevel 2
Badge +17

Hi @abu_de_bdlq_16, if the requirement is to classify the cells of a grayscale raster into five classes by four threshold values and replace cell values with specific colors associated to each class, this workflow might be helpful.

Notes:

  • Modify the thresholds in the expression according to the actual demand.
  • See the help on the RasterPaletteExtractor transformer to learn about the syntax for palette definitions.

upper: source raster, lower: result

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