How do you use the color_ramp raster function on raster's with multiple bands?

JBuchanan — Fri, 07 Jul 2023 21:47:29 GMT

I am attempting to apply color ramps to raster files in my project. The stretch renderer allows for applying color ramps to rasters, but currently only has 3 preset options. Alternatively, I have been applying color ramps to my rasters using raster functions. However, I have only been able to load the symbology of a raster layer in runtime if the symbology is RGB. If I configure the symbology as Stretch, Unique Values, Colormap, or Classify, then the layer is loaded into runtime with no symbology, aka the layer is black/white. Raster layers with RGB symbology have multiple bands and my raster functions won't apply to rasters with more than 1 color band.

I am currently using the example color_ramp function format from: Add raster data | ArcGIS Maps SDK for .NET | ArcGIS Developers

{ "raster_function":{"type":"Color_ramp_function"}, "raster_function_arguments": { "resizable":{"bool":false,"type":"Raster_function_variable"}, "color_ramp": { "color_ramp": { "ramps": [ {"to_color":[0,255,0],"from_color":[0,191,191],"num_colors":3932,"type":"Algorithmic_color_ramp","algorithmic_type":"hsv"}, {"to_color":[255,255,0],"from_color":[0,255,0],"num_colors":3932,"type":"Algorithmic_color_ramp","algorithmic_type":"hsv"}, {"to_color":[255,127,0],"from_color":[255,255,0],"num_colors":3932,"type":"Algorithmic_color_ramp","algorithmic_type":"hsv"}, {"to_color":[191,127,63],"from_color":[255,127,0],"num_colors":3932,"type":"Algorithmic_color_ramp","algorithmic_type":"hsv"}, {"to_color":[20,20,20],"from_color":[191,127,63],"num_colors":3935,"type":"Algorithmic_color_ramp","algorithmic_type":"hsv"} ], "type":"Multipart_color_ramp" }, "type":"Raster_function_variable" }, "raster":{"name":"raster","is_raster":true,"type":"Raster_function_variable"}, "type":"Raster_function_arguments" }, "type":"Raster_function_template" }

The issue is that if my raster contains multiple bands, then the raster function throws up an error such as "Band Count is 3."

Is there an issue with my raster function?
Should I be adding some optional Raster Function Argument to allow for multiband rasters?
Are there even other arguments other than "resizable" and "color_ramp"?

My application is offline, so I can't use an image service to handle raster functions.

Re: How do you use the color_ramp raster function on raster's with multiple bands?

DiveshGoyal — Mon, 10 Jul 2023 18:12:17 GMT

One approach would be to combine a bunch of raster functions to accomplish this - Extract Band + Color Ramp + Composite Band

Use Extract Band function to create a single raster for each band in your source data
Use Color Ramp function to colorize each single-band raster created above
Use Composite Band function to combine all single-band rasters into a multi-band raster.

See https://developers.arcgis.com/net/layers/add-raster-data/#supported-raster-functions for function syntax

topic How do you use the color_ramp raster function on raster's with multiple bands? in .NET Maps SDK Questions

How do you use the color_ramp raster function on raster's with multiple bands?

Re: How do you use the color_ramp raster function on raster's with multiple bands?