topic Re: NoData setting differs according to file format in raster save method in Data Management Questions

NoData setting differs according to file format in raster save method

YasunariMorita — Thu, 06 Jul 2017 07:53:13 GMT

Hi,

I tried to make masked raster.

At first, making mask raster, and then SetNull for input raster.It's very common process.

All processes is well ,but NoData setting differs according to file format in raster save method....

I've checked following two format.

ESRI Gird:output raster has no problem, NoData pixels are not displayed in ArcMap.
TIF: Not working NoData value. NoData pixels have values(-3.4028235e+038 or 0). So, NoData pixels are displayed in ArcMap.

Unfortunately, I need to save in TIF format ,so it is just the problem.

I tried arcpy.env.nodata setting. However, Noting had changed.

What should I do?

# -*- coding: utf-8 -*-
# Import arcpy module
import arcpy
import sys
import os
class LisenceError(Exception):
  pass
# Check Spatial Analyst license
try:
  if arcpy.CheckExtension("Spatial") == "Available":
    arcpy.CheckOutExtension("Spatial")
  else:
    # raise a custom extension
    raise LisenceError
except LisenceError:
  print("Spatial Analyst License is unavailable")
  arcpy.AddMessage("Spatial Analyst License is unavailable")

def makeCoheMask(coheRas, ccthresh):
  try:
    coheMask = arcpy.sa.Con(arcpy.Raster(coheRas) < ccthresh, 0, 1)
    return coheMask
  except arcpy.ExecuteError:
    print(arcpy.GetMessages(2))

def makeSlopeMask(dem, geoid, angle, heightType, zfactor):
  try:
    arcpy.env.cellSize = "MINOF"
  TMP_SLOPE = arcpy.env.scratchWorkspace + '\\tmp_slope'
arcpy.Slope_3d(dem, TMP_SLOPE, 'DEGREE', zfactor)
    return slopeMask
  except arcpy.ExecuteError:
    print(arcpy.GetMessages(2))

def makeLSMask(lsData, type):
  try:
      outRas = arcpy.sa.Con(arcpy.Raster(lsData) > 1, 0, 1)
      return outRas
  except arcpy.ExecuteError:
    print(arcpy.GetMessages(2))

# Set overwrite option
arcpy.env.overwriteOutput = True
# Arguments
inputRas = sys.argv[1]
coheFlg = sys.argv[2]
coheRas = sys.argv[3]
ccthresh = sys.argv[4]
slopeFlg = sys.argv[5]
dem = sys.argv[6]
zfactor = sys.argv[7]
angle = sys.argv[8]
lsFlg = sys.argv[9]
lsData = sys.argv[10]
output = sys.argv[11]
try:
  input_Raster = arcpy.Raster(inputRas)

  if coheFlg.lower() == 'true':
    mask_cohe = makeCoheMask(coheRas, float(ccthresh))
  else:
    arcpy.AddMessage('NOT applied coherence mask')
    mask_cohe = 1

  if slopeFlg.lower() == 'true':
    mask_slope = makeSlopeMask(dem, geoid, float(angle), heightType, float(zfactor))
  else:
    arcpy.AddMessage('NOT applied slope mask')
    mask_slope = 1

  if lsFlg.lower() == 'true':
    mask_ls = makeLSMask(lsData, type)
    arcpy.AddMessage('finish making LS mask')
  else:
    arcpy.AddMessage('NOT applied LS mask')
    mask_ls = 1

  conRas = arcpy.sa.Int(mask_cohe * (mask_slope * mask_ls))
  outSetNull = arcpy.sa.SetNull(conRas, input_Raster, "VALUE = 0")

  outSetNull.save(output)

  if arcpy.Exists(TMP_SLOPE):
    arcpy.Delete_management(TMP_SLOPE)
except arcpy.ExecuteError:
  print(arcpy.GetMessages(2))

Re: NoData setting differs according to file format in raster save method

DanPatterson_Retired — Thu, 06 Jul 2017 10:34:53 GMT

Nodata does vary based on the type of grid saved since

http://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/nodata-in-raster-datasets.htm

you can control it through the environment settings

http://desktop.arcgis.com/en/arcmap/latest/tools/environments/nodata.htm

then you can refer to prior to using SetNull

http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/set-null.htm

Re: NoData setting differs according to file format in raster save method

YasunariMorita — Fri, 07 Jul 2017 05:46:43 GMT

Thanks your reply

I set arcpy.env.nodata prior to using SetNull, trying all method, but I couldn't solve the problem...

(I think arcpy.env.nodata = "NONE" is valid in this case, is my understanding correct?)

I guess arcpy.env.nodata could not work in my script, but why?

Re: NoData setting differs according to file format in raster save method

DanPatterson_Retired — Fri, 07 Jul 2017 11:28:44 GMT

you indicate that nodata values are displayed... that should now a symbology issue

http://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/symbolizing-values-of-nodata-in-raster-datasets.htm

which doesn't have a solution within arcpy except for using a lyr file.

Can you confirm that the nodata values are truly nodata or are they now being treated as values?

Re: NoData setting differs according to file format in raster save method

YasunariMorita — Wed, 12 Jul 2017 01:51:28 GMT

Sorry for my poor explanation

I'm afraid it's not a symbology issue, but, nodata values(i.e -3.40282e+038) are treated as valid value.

-3.40282e+038 is treated as valid value...

Of course, I set nodata symbol transparent.

nodata setting in this test data are below

input : 0(32bit float)

mask:nothing(1bit value 0or1)

0 has two meaning.Therefore I assigned -9998 to nodata of input raster.

But,it didn't work...

Re: NoData setting differs according to file format in raster save method

DanPatterson_Retired — Wed, 12 Jul 2017 03:09:10 GMT

this is what the no data value should have been set to, the largest negative number

-3.40282e+038

Re: NoData setting differs according to file format in raster save method

YasunariMorita — Wed, 09 Aug 2017 08:38:30 GMT

Thanks Dan!

during process, no data value is set to.(assigned many values)

So, I use arcpy.SetRasterProperties_management() for every output in script.

Everything goes well!

Re: NoData setting differs according to file format in raster save method

DanPatterson_Retired — Wed, 09 Aug 2017 11:19:04 GMT

glad it worked out! you should close this thread out so that people know a solution was found