Raster calculator - complex conditional statement

Question

Raster calculator - complex conditional statement I need help creating a raster calculator syntax. I want to normalize precipitation values with the mean for specific altitude-classes: I have two input rasters 1: reclassified dtm, with 1==0>dtm<200, 2==200>dtm<400, 3==400>dtm<600, ???10== if 1800>dtm<2000, 11== dtm>2000 2: precipitation. I want to create a statement like ???if reclassified dtm=1, precipitation should be divided by the value for the average precipitation in 0-200m altitude, if reclassified dtm=2, precipitation should be divided by the value for the average precipitation in 200-400m altitude, ???. and if reclassified dtm=11, precipitation should be devided by the value for the average precipitation in >2000m altitude.??? Is there any way this can be done in raster calculator? (I have already done statistics to find average precipitation in the different altitudes and reclassified a dtm)

JonDra · Answer

It worked for me if I wrote it like this:
Con("dmt_reclass" == 1, "precipitation" / 270, Con("dmt_reclass" == 2, "precipitation" / 420, Con("dmt_reclass"==3, "precipitation" / 540)))
So a nested statement that is.

I haven't tried the zonal statistics tool with the raster calculator curtvprice, but I'm going to look into it!

Thanks for the help guys!

curtvprice · Answer

I want to normalize precipitation values with the mean for specific altitude-classes: I have two input rasters 1: reclassified dtm, with 1==0>dtm<200, 2==200>dtm<400, 3==400>dtm<600, �?�10== if 1800>dtm<2000, 11== dtm>2000 2: precipitation. I want to create a statement like if reclassified dtm=1, precipitation should be divided by the value for the average precipitation in 0-200m altitude, else if reclassified dtm=2, precipitation should be divided by the value for the average precipitation in 200-400m altitude, ... if reclassified dtm=11, precipitation should be devided by the value for the average precipitation in >2000m altitude. Is there any way this can be done in raster calculator? (I have already done statistics to find average precipitation in the different altitudes and reclassified a dtm) You could do this with nested Con statements, or the Pick tool, but I believe there is an easier way. The Zonal Statistics tool replicates the mean for the zone for all cells in the zone -- so you can do this with the Raster Calculator tool: float("precip") / ZonalStatistics("reclass_dtm", "VALUE", "precip", "MEAN")

JonDra · Answer

I had a tip about how to write an expression:
Con("dmt_reclass" == 1, "precipitation" / 270) & Con("dmt_reclass" ==  2, "precipitation" / 420) & .....
Where dmt_reclass is of course my reclassified dmt. 270 is the average precipitation in dmt_reclass 1 and so on.

But this won't work for me, my result is just a raster with a novalue it seems like.
I'm totally new to coding these, so I don't know what I'm doing wrong.