Dear FME-Users,
I’ve 3 input rasters with the same CRS, extension and resolution.
The aim is to get 1 output raster by combining all pixel values.
For each pixel the highest value from the import rasters should be used.
In the attachment you’ll find 3 rasters. The color cyan is “low” and the colors to red are “higher”.
Do you have an idea?
Thank you so much.
Best regards!
Konrad
Best answer by takashi
Hi @abu_de_bdlq_16, fortunately the three rasters have exactly same extents, resolution, and palette, and also the palette entry is ordered by color - i.e. from cyan (low) to red (high). In this condition, I think the RasterExpressionEvaluator would be a good solution, as the articles @itay linked describe. e.g.
Result:
In FME 2017, the RasterMosaicker could also be another solution. Coming soon :-)
+7Hi @abu_de_bdlq_16
I think the way to go is to split the raster into cells and calculate the with the StatisticsCalculator the maximum value per row / column combination (group by). This maximum value can then be used to create the final raster.
This is just a possible solution. I am sure others (@takashi) have better / more readable solutions.
+18Hi @abu_de_bdlq_16,
I would have a look at the RasterCellValueCalculator or the RasterExpressionEvaluator.
This is an efficient way to calculate on rasters.
Some articles on the matter are:
https://knowledge.safe.com/articles/1272/simple-examples-using-the-rasterexpressionevaluato.html
https://knowledge.safe.com/articles/1222/combining-rasters-with-the-rasterexpressionevaluat.html
https://knowledge.safe.com/articles/1226/using-conditions-with-the-rasterexpressionevaluato.html
Hope this helps.
Hi @abu_de_bdlq_16, fortunately the three rasters have exactly same extents, resolution, and palette, and also the palette entry is ordered by color - i.e. from cyan (low) to red (high). In this condition, I think the RasterExpressionEvaluator would be a good solution, as the articles @itay linked describe. e.g.
Result:
In FME 2017, the RasterMosaicker could also be another solution. Coming soon :-)
+40In FME 2016 and earlier I would use the rasterBandCombiner to merge the files into one raster followed by a RasterExpressionEvaluator to get the max value of the 3 bands.
In FME 2017 I would look at the RasterMosaicker with overlapping values set to Max
Thank your very much @takashi, now it works. I thank also @jeroenstiers, @itay and @jdh for your support. :)
Best regards!
Konrad
+18Hi @abu_de_bdlq_16, fortunately the three rasters have exactly same extents, resolution, and palette, and also the palette entry is ordered by color - i.e. from cyan (low) to red (high). In this condition, I think the RasterExpressionEvaluator would be a good solution, as the articles @itay linked describe. e.g.
Result:
In FME 2017, the RasterMosaicker could also be another solution. Coming soon :-)
