I'm trying to display a number of sea level scenarios to discuss landscape differences across time. I've created a CTM of the region now I need to display sea level at a number of reduced levels (e.g. -50m).
I've already tried extract by attribute using "value <=-50" which produces a number of error problems which seem to be related to the GDB, but I can't get round them. Could extract by mask be better?
Does anyone have a simpler or better way? In an ideal scenario I would like to display the final model with terrain changes displayed for the terrestrial data but the sea can be extracted as no data and displayed blue. However it can simply be a blue green display just showing coastline if that is the best way using ArcMap 10.3, Windows 8.
Answer
There are many approaches you could use to extract portions of your surface model. With Raster Calculator, you could extract cells based on values. For instance, with the Con() statement you could do something like this:
Con("CTM_Raster" <= -50, 1, 0)
This will generate a new raster with a value of 1 for values less than -50, and 0 for those greater. Of course, you will need to change the name of the raster. This can then be used to create a polygon if desired. And as I said, there are other ways.
If you wish to retain the original raster values, you can do the following:
Con("CTM_Raster" <= -50, "CTM_Raster", 0)
This will generate a raster with the original values below -50, and a value of 0 above.
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