topic Re: Problem with raster Reclassify in python script in ArcGIS Spatial Analyst Questions

Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Sun, 12 Dec 2021 01:43:18 GMT

Cross posting: Python

I'm writing a python tool that given a elevation raster (elevation value in meters), converts to a "raster object" with elevation value in feet. I then create a variable based on elevation Range provided be the user to be used with the Reclassify command as a RemapRange. The result of this Reclassify (and maybe one other step eventually) will be input to RasterToPolygon

I've included a very simplified version of the code I have,

The out value of my reclassArg is

[[327.850126532, 1000, 1000], [1000, 2000, 2000], [ 2000, 3000, 3000], [ 3000, 6500, 6500]]

But I have also tried version such as

327.850126532 1000 1000; 1000 2000 2000; 2000 3000 3000; 3000 6500 6500

and all different variations of the two, based on the "results" snippet, and various help docs.

I've tried quite a few different commands and versions of the reclassArg, with the last being from the local ArcGIS 10.3 tool help

But my output raster keeps come out with a single value 127. Full disclosure, before I tried

outDEMtmp = Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")

outDEMtmp = arcpy.sa.Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")

and even

arcpy.gp.Reclassify_sa(elevFeet, "Value", reclassArg, outDEMtmp, "NODATA")

The first two (using the [[ ]] list as reclassArg) finishes without an erro, but all values are are "127"

The third option is not reclassifying anything.

I admit my spatial analyst skills are very rusty, and the raster-object concept is new (all though similar to the old GRID), but I'm running out of ideas to try, other than running the tools manually. Any help or a good resource on scripting the Reclassify tool would be helpful.

Using 10.3, ArcInfo/Advanced and Spatial Analyst (I have access to 3D if needed).

import os
import arcpy
from arcpy import env
from arcpy.sa import *

arcpy.CheckOutExtension("spatial")

theWorkspace = r"C:\_beartest\Prep.gdb"
arcpy.env.workspace = theWorkspace
arcpy.env.overwriteOutput = True
wsPath, wsGDB = os.path.split(theWorkspace)

rasterIn = r"C:\_beartest\Unit20Araster.gdb\elevClip"

toElevFeet = 3.280839895013123

elevFeet = (Raster(rasterIn) * toElevFeet)
elevMinimum = elevFeet.minimum

elevCutoffFt = "6500"
flatElevBreak = ("1000; 2000; 3000")

# processing the elevation and high-cuttoff variables to create reclass arguments
elevSplit = flatElevBreak.split(";")
lstCnt = 1
for reclassValue in elevSplit:
    print(reclassValue)
    print("Reclass value:{0} ft".format(reclassValue))
    if lstCnt == 1:
        reclassArg = ("[[{0}, {1}, {2}]".format(elevMinimum, reclassValue, ("{0}".format(reclassValue))))
    else:
        reclassArg = ("{0}, [{1}, {2}, {3}]".format(reclassArg, prevValue, reclassValue, ("{0}".format(reclassValue))))
    lstCnt += 1
    prevValue = reclassValue
reclassArg = ("{0}, [{1}, {2}, {3}]]".format(reclassArg, prevValue, elevCutoffFt, ("{0}".format(elevCutoffFt))))
print(reclassArg)

outDEMtmp = arcpy.sa.Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")
outDEMtmp.save(elevReclass)

print("hello2")
#arcpy.RasterToPolygon_conversion(outDEMtmp, "reclassPoly", "SIMPLIFY", "VALUE")

arcpy.CheckInExtension("spatial")

Suggestions would be greatly appreciated. Thanks

EDIT: added line 18 which was missing.

Message was edited by: Rebecca Strauch, GISP EDIT: added line 18 which was missing.

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 00:52:39 GMT

you are reclassing ranges to the higher of the range...correct? (it should be a list of lists)

can you show the results of your print statements? and perhaps whip in a few more at the various stages

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Sun, 12 Dec 2021 01:43:21 GMT

Hi Dan, running this in the ArcMap python window....

>>> import os
... import arcpy
... from arcpy import env
... from arcpy.sa import *
... 
... arcpy.CheckOutExtension("spatial")
... 
... theWorkspace = r"C:\_beartest\Prep.gdb"
... arcpy.env.workspace = theWorkspace
... arcpy.env.overwriteOutput = True
... wsPath, wsGDB = os.path.split(theWorkspace)
... 
... rasterIn = r"C:\_beartest\Unit20Araster.gdb\elevClip"
... 
... toElevFeet = 3.280839895013123
... 
... elevFeet = (Raster(rasterIn) * toElevFeet)
... elevMinimum = elevFeet.minimum
... 
... elevCutoffFt = "6500"
... flatElevBreak = ("1000; 2000; 3000")
... 
... # processing the elevation and high-cuttoff variables to create reclass arguments
... elevSplit = flatElevBreak.split(";")
... lstCnt = 1
... for reclassValue in elevSplit:
...     print(reclassValue)
...     print("Reclass value:{0} ft".format(reclassValue))
...     if lstCnt == 1:
...         reclassArg = ("[[{0}, {1}, {2}]".format(elevMinimum, reclassValue, ("{0}".format(reclassValue))))
...     else:
...         reclassArg = ("{0}, [{1}, {2}, {3}]".format(reclassArg, prevValue, reclassValue, ("{0}".format(reclassValue))))
...     lstCnt += 1
...     prevValue = reclassValue
... reclassArg = ("{0}, [{1}, {2}, {3}]]".format(reclassArg, prevValue, elevCutoffFt, ("{0}".format(elevCutoffFt))))
... print(reclassArg)
... 
... outDEMtmp = arcpy.sa.Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")
... #outDEMtmp.save(elevReclass)
... 
... print("hello2")
... #arcpy.RasterToPolygon_conversion(outDEMtmp, "reclassPoly", "SIMPLIFY", "VALUE")
... 
... arcpy.CheckInExtension("spatial")
... 
1000
Reclass value:1000 ft
 2000
Reclass value: 2000 ft
 3000
Reclass value: 3000 ft
[[327.850126532, 1000, 1000], [1000,  2000,  2000], [ 2000,  3000,  3000], [ 3000, 6500, 6500]]
hello2
>>>

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 01:13:40 GMT

I am trying to figure out where the 127 is coming from (I have my suspicions). Can you change the reclass value ranges by putting a decimal point in the number range and convert to an integer output class ie( 1000.0, 2000.0, 2) just for fun.

Curtis Price if you are around, can you pin this down?

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Wed, 04 Nov 2015 01:33:11 GMT

Good thought Dan. At least I'm getting an error now. If I have the reclassArg as

[[327.850126532, 1000.0, 1000], [1000.0, 2000.0, 2000], [ 2000.0, 3000.0, 3000], [ 3000.0, 6500.0, 6500]]

inputting it into the same command...

outDEMtmp = arcpy.sa.Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")

I am now getting error

I tried simplifying it more, as you suggested and getting same error.

reclassArg = "(1000.0, 2000.0, 2)"

print ("new reclassArg: {0}".format(reclassArg))

outDEMtmp = arcpy.sa.Reclassify(elevFeet, "Value", RemapRange("{0}".format(reclassArg)), "NODATA")

I got the same error. So, I'm trying a few more reclass command combinations to see if it will make any difference.

grrrrrrrrr......

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 01:48:48 GMT

Do you have to send it as a string representation of a tuple, since you can send the tuple directly

>>> reclassArg = (1000.0,2000.0,2)

>>> print("new version: {}".format(reclassArg))

new version: (1000.0, 2000.0, 2)

and since you only have one parameter, you need not specify the parameter number unless you are providing things out of order. eg....

>>> ObiSpeak = ["Confused", "am", "I"]

>>> print("{2} {1} {0}".format(*ObiSpeak))

I am Confused

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Wed, 04 Nov 2015 01:52:08 GMT

I'm at a loss.

Dan/Curtis, et al., please send any suggestions if you have them, but time to put in a tech support ticket. Most likely it is my just interpreting the help somehow, but having it comes out as one big 127 value has really got me stumped. I even tried running it against the original elevation raster (meters) and it came out the same, so it has to be something with my range argument.

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Wed, 04 Nov 2015 01:56:23 GMT

Thanks Dan.

reclassArg = (1000.0,2000.0,2)

fff = arcpy.sa.Reclassify("elevClip", "Value", RemapRange("{0}".format(reclassArg)),"NODATA")

Still came out as 127.

BTW, I know the {#} isn't necessary, but I find its a good habit for me to be in so I don't screw up when I do reorder. Doesn't hurt anything, IMO.

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 01:59:10 GMT

hmmmm ringing a bell

Re: Reclassify raster - floating point to categorical

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Wed, 04 Nov 2015 02:18:16 GMT

That is helpful, but still not fixing things. But now I'm starting to think is is how I am building the reclassArg value. if I set a new value to the value of reclassArg and follow hints in the other thread, it clearly shows that my variable is not seeing it as a list. Looks like I need to work on the formatting, then test again

>>>reclassArg

'[[327.850126532, 1000.0, 1000], [1000.0, 2000.0, 2000], [ 2000.0, 3000.0, 3000], [ 3000.0, 6500.0, 6500]]'

>>> zzz = '[[327.850126532, 1000.0, 1000], [1000.0, 2000.0, 2000], [ 2000.0, 3000.0, 3000], [ 3000.0, 6500.0, 6500]]'

>>> remap = RemapRange(zzz)

>>> remap

RemapRange([['['], ['['], ['3'], ['2'], ['7'], ['.'], ['8'], ['5'], ['0'], ['1'], ['2'], ['6'], ['5'], ['3'], ['2'], [','], [' '], ['1'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], ['1'], ['0'], ['0'], ['0'], [']'], [','], [' '], ['['], ['1'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], [' '], ['2'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], [' '], ['2'], ['0'], ['0'], ['0'], [']'], [','], [' '], ['['], [' '], ['2'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], [' '], ['3'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], [' '], ['3'], ['0'], ['0'], ['0'], [']'], [','], [' '], ['['], [' '], ['3'], ['0'], ['0'], ['0'], ['.'], ['0'], [','], [' '], ['6'], ['5'], ['0'], ['0'], ['.'], ['0'], [','], [' '], ['6'], ['5'], ['0'], ['0'], [']'], [']']])

So, at least that helps...maybe.

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 02:27:15 GMT

check my format string which doesn't cast the variable as a string which yours does, it casts it as a tuple. If you build the table as in curtis's example then you should have the format you need Curtis should be online soon

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Wed, 04 Nov 2015 02:43:15 GMT

I tried that, but that didn't help any. Still getting 127. I've tried various versions of the reclassArg formatting and using the remap = and using the RemapRange(reclassArg) with various formatting...both with .0 and without. All either they come out as 127 or it just doesn't reclass.

Maybe Curtis will have some other ideas. Otherwise, hopefully tech support will have some ideas. I'm getting close to giving up for the night.

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 02:54:22 GMT

I was thinking about his idea of doing it all at once, after building the remap table

eg.

remap = RemapRange([[1000, 2000, 1], [2000, 3000, 2], [3000, 4000, 3]]

out_reclass = Reclassify(raster, "Value", remap, "NODATA")

Re: Problem with raster Reclassify in python script

RebeccaStrauch__GISP — Sun, 12 Dec 2021 01:43:23 GMT

So, that worked, but I need to get my reclassArg, which will be created on the fly, into that format. I've been working on that.

EDIT: after quite a bit more manipulation in getting my reclassArg into a list, I also realized for some reason it wants the new value to not be the same as my reclassValue. No sure what the reason is for that right now, but at least now I might be able to clean it up and get it to work in the morning.

EDIT2: cleaned up script a little...this is a snippet of what ended up working. Super quick now, so I can now continue on. Thanks for you help Dan (and Curtis Price via the other thread). It was my reclassArg not being formatted correctly all along.

flatElevBreak = ("1000; 2000; 3000")

elevFeet = (Raster(rasterIn) * toElevFeet)
elevMin = elevFeet.minimum
elevMax = elevFeet.maximum  
print("\n Elevation raster source: {0}".format(elevFeet))

# processing the elevation and high-cuttoff variables to create reclass arguments
elevSplit = flatElevBreak.split(";")
lstCnt = 1
reclassArg = []
for reclassValue in elevSplit:
    print(reclassValue)
    print("Reclass value:{0} ft".format(reclassValue))
    if lstCnt == 1:
        reclassArg.append([int(elevMin), int(reclassValue), lstCnt])
    else:
        reclassArg.append([int(prevValue), int(reclassValue), lstCnt])
    lstCnt += 1
    prevValue = reclassValue
reclassArg.append([int(prevValue), int(elevCutoffFt), lstCnt])
reclassArg.append([int(elevCutoffFt), int(elevMax), 9])
print("{0}".format(reclassArg))
remap  = RemapRange(reclassArg)
print("{0}".format(remap))

# Process: Reclassify
outDEMtmp = Reclassify(elevFeet, "Value", remap, "NODATA")

print("hello2")
arcpy.RasterToPolygon_conversion(outDEMtmp, "reclassPoly", "SIMPLIFY", "VALUE")

Dan, no need to keep refining the code...it works, it's readable...time for me to move on.

Re: Problem with raster Reclassify in python script

DanPatterson_Retired — Wed, 04 Nov 2015 03:26:18 GMT

sorry It is late, I was thinking about how you put it together as well

minelev = 649

elevs = [1000,2000,3000]

elevs.insert(0,minelev)

remap = [[elevs[i-1],elevs,elevs] for i in range(1,len(elevs))]

print("remap ... {}".format(remap))

#out_reclass = Reclassify(raster, "Value", remap, "NODATA") # then do this thing

print yields remap ... [[649, 1000, 1000], [1000, 2000, 2000], [2000, 3000, 3000]]

ADDENDUM

an example from one of Curtis's remap examples for weighted overlay

Re: Assign Dynamic Influence % to Weighted Overlay Table for Weighted Overlay Analysis