topic Re: raster calculator on the raster file having 17 values in ArcGIS Spatial Analyst Questions

raster calculator on the raster file having 17 values

Chang-HengYang — Thu, 06 Aug 2015 22:27:12 GMT

Hi All,

I want to use the Raster Calculator to process the raster with 17 different values (Please see the attached file). I want to multiply each raster value (from 1 to 17) by different values. Please let me know your opinions.

Thanks,

Hank

Re: raster calculator on the raster file having 17 values

DarrenWiens2 — Thu, 06 Aug 2015 22:32:19 GMT

Is there some pattern to the values you want to multiply, or somewhat random? If a pattern, you can potentially build a map algebra expression to handle all cases, if random, you may want the Reclassify tool, but it really depends on exactly what you want.

Save us some time and post what you've tried, or at least, provide more information on your specific requirements.

Re: raster calculator on the raster file having 17 values

DanPatterson_Retired — Thu, 06 Aug 2015 22:41:52 GMT

Q Multiplication has a synonym ... what is it?

A Times—Help | ArcGIS for Desktop

and do what Darren says...

Re: raster calculator on the raster file having 17 values

JayantaPoddar — Fri, 07 Aug 2015 06:16:54 GMT

Hello Chang,

You might like to use conditional statements in Raster Calculator

e.g. In case of random values

Con([raster1]=1, [raster1]*n1, (Con([raster1]=2, [raster1]*n2, (Con([raster1]=3, [raster1]*n3, (........(Con([raster1]=17, [raster1]*n17)))))))))))))))))

where raster1: name of the input raster

n1...n17: values (You could also write another expression in n1, if required)

Building expressions in Raster Calculator

Re: raster calculator on the raster file having 17 values

Chang-HengYang — Fri, 07 Aug 2015 15:52:23 GMT

Hi all,

Thank you for your all responses.

value 2: 0.4615

value 3: 3.2754

value 4: 0.5548

value 5: 2.4472

value 6: 4.9880

value 7: 5.9763

value 8: 4.0460

value 9: 0.1981

value 10: 3.1018

value 11: -1.2635

value 12: 2.5069

value 13: 2.9155

value 14: 0.7207

value 15: 1.4548

value 16: 0.5179

value 17: 1.1133

If I want to use the con in the raster calculator. please let me know if my formula is correct.

assuming the raster of interest is named as raster

con([raster]=2, [raster]*0.4615,

con ([raster]=3, [raster]*3.2754,

con([raster]=4, [raster]*0.5548,

con([raster]=5, [raster]*2.4472,

con ([raster]=6, [raster]*4.9880,

con([raster]=7, [raster]*5.9763,

con([raster]=8, [raster]*4.0460,

con ([raster]=9, [raster]*0.1981,

con([raster]=10, [raster]*3.1018,

con([raster]=11, [raster]*-1.2635,

con ([raster]=12, [raster]*2.5069,

con([raster]=13, [raster]*2.9155,

con([raster]=14, [raster]*0.7207,

con ([raster]=15, [raster]*1.4548,

con([raster]=16, [raster]*0.5179,

con([raster]=17, [raster]*1.1133))))))))))))))))

However, I get the error message, ERROR 000539: Runtime error DyntaxError: keyword can not have an expression

Please let me know how I fix this error.

Thanks,

Changheng

Re: raster calculator on the raster file having 17 values

JayantaPoddar — Fri, 07 Aug 2015 16:02:25 GMT

Try this!

con([raster]==2, [raster]*0.4615, (con([raster]==3, [raster]*3.2754, (con([raster]==4, [raster]*0.5548, (con([raster]==5, [raster]*2.4472, (con([raster]==6, [raster]*4.9880, (con([raster]==7, [raster]*5.9763, (con([raster]==8, [raster]*4.0460, (con([raster]==9, [raster]*0.1981, (con([raster]==10, [raster]*3.1018, (con([raster]==11, [raster]*(-1.2635), (con([raster]==12, [raster]*2.5069, (con([raster]==13, [raster]*2.9155, (con([raster]==14, [raster]*0.7207, (con([raster]==15, [raster]*1.4548, (con([raster]==16, [raster]*0.5179, (con([raster]==17, [raster]*1.1133))))))))))))))))

Re: raster calculator on the raster file having 17 values

DarrenWiens2 — Fri, 07 Aug 2015 16:05:41 GMT

Change all = to ==, and of course, change [raster] to the name of your raster.

An overview of the Map Algebra Operators—Help | ArcGIS for Desktop

Re: raster calculator on the raster file having 17 values

JayantaPoddar — Fri, 07 Aug 2015 16:34:07 GMT

Thanks Darren,

Changed the script above accordingly. Missed it earlier

Re: raster calculator on the raster file having 17 values

Chang-HengYang — Fri, 07 Aug 2015 16:37:29 GMT

Two tricks

1. no []

2. use ==

Thank you all the efforts.

Changheng

Con("GeoUnits_class.tif"==2, "GeoUnits_class.tif"*0.4615,

Con ("GeoUnits_class.tif"==3, "GeoUnits_class.tif"*3.2754,

Con("GeoUnits_class.tif"==4, "GeoUnits_class.tif"*0.5548,

Con("GeoUnits_class.tif"==5, "GeoUnits_class.tif"*2.4472,

Con ("GeoUnits_class.tif"==6, "GeoUnits_class.tif"*4.9880,

Con("GeoUnits_class.tif"==7, "GeoUnits_class.tif"*5.9763,

Con("GeoUnits_class.tif"==8, "GeoUnits_class.tif"*4.0460,

Con ("GeoUnits_class.tif"==9, "GeoUnits_class.tif"*0.1981,

Con("GeoUnits_class.tif"==10, "GeoUnits_class.tif"*3.1018,

Con("GeoUnits_class.tif"==11, "GeoUnits_class.tif"*-1.2635,

Con ("GeoUnits_class.tif"==12, "GeoUnits_class.tif"*2.5069,

Con("GeoUnits_class.tif"==13, "GeoUnits_class.tif"*2.9155,

Con("GeoUnits_class.tif"==14, "GeoUnits_class.tif"*0.7207,

Con ("GeoUnits_class.tif"==15, "GeoUnits_class.tif"*1.4548,

Con("GeoUnits_class.tif"==16, "GeoUnits_class.tif"*0.5179,

Con("GeoUnits_class.tif"==17, "GeoUnits_class.tif"*1.1133))))))))))))))))