topic Re: how to enter 'rectangle' argument in raster Clip in ArcGIS Spatial Analyst Questions

how to enter 'rectangle' argument in raster Clip

DarleneWilcox — Wed, 07 Sep 2016 22:30:10 GMT

I have a raster that I want to clip to a county boundary (no data outside county). It is a stretched NDVI tif, so the values of the raster are 0-255. I tried using the Con function, but it produced an output raster with values from 6 to 66500-ish. I determined that what would work is the raster Clip tool and checking the 'Use Input Features for Clipping Geometry' box. The results are fine -- no data outside the county, correct values inside the county -- EXCEPT that the extent of the output raster is the extent of the county polygon, and I want it to be a different, larger extent (so as to be the same size as other raster datasets).
The Python Snippet comes out like this:
# Replace a layer/table view name with a path to a dataset (which can be a layer file) or create the
# layer/table view within the script.
# The following inputs are layers or table views: "...a.tif", "...b.shp"
arcpy.Clip_management(in_raster="...a.tif", rectangle="677439.999999999 3721040 678360.000000007 3722960", out_raster="...c.tif", in_template_dataset="b.shp", nodata_value="256", clipping_geometry="ClippingGeometry", maintain_clipping_extent="NO_MAINTAIN_EXTENT")
I can replace all the dataset arguments with variables:
theInRaster = ...a.tif
theCntyShp = ...b.shp
theOutRaster = ...c.tif
arcpy.Clip_management(in_raster= theInRaster",
rectangle="677439.999999999 3721040 678360.000000007 3722960",
out_raster=theOutRaster,
in_template_dataset=theCntyShp,
nodata_value="256", clipping_geometry="ClippingGeometry",
maintain_clipping_extent="NO_MAINTAIN_EXTENT")
Now, I want the rectangle argument to be equal to the extent of clip.tif. I tried setting the arcpy.env.extent to clip.tif and leaving the rectangle argument blank (""), but it went to the smaller extent of the polygon. So, I need to actually put 'something' in the rectangle coordinates. I tried setting theExtent to several things:
theExtent = arcpy.env.extent and then rectangle = theExtent #crashed ArcGIS completely
theExtentRaster = ...clip.tif and then rectangle = theExtentRaster #crashed ArcGIS completely
theDesc = arcpy.Describe(theExtentRaster)
theExtent = theDesc.extent and then rectangle = theExtent
or
theDesc = arcpy.Describe(theExtentRaster)
theExtent = theDesc.extent and then rectangle = theExtent
theExtentString = str(theExtent.XMin) + ' ' + str(theExtent.YMin) + ' ' + str(theExtent.XMax) + ' ' + str(theExtent.YMax) and then rectangle = theExtentString
and also trying adding either single quotes or double quotes to theExtentString
all result in this error:
ExecuteError: ERROR 000622: Failed to execute (Clip). Parameters are not valid. ERROR 000628: Cannot set input into parameter rectangle.
So, clearly, there is SOME OTHER WAY to define the rectangle. I'm hoping someone out there can help.... Thanks.

Re: how to enter 'rectangle' argument in raster Clip

DanPatterson_Retired — Wed, 07 Sep 2016 22:41:37 GMT

use the extent object of the desired raster directly as shown in the example script here Raster—Help | ArcGIS for Desktop you can also examine the extent object if your wish as well, Extent—Help | ArcGIS for Desktop

Re: how to enter 'rectangle' argument in raster Clip

DarleneWilcox — Thu, 08 Sep 2016 14:39:08 GMT

Dan, I know I need to use the extent -- I just can't get the arcpy.Clip_management command to accept the extent in the rectangle argument! Of course I can enter it manually -- I need to do it within a script. It is a formatting thing -- how to format the XMin YMin XMax YMax so as not to either crash ArcGIS completely, as occurs when I tried using

arcpy.env.extent = ...clip.tif

theExtent = arcpy.env.extent

theExtent = clip.tif

And if I try building the string of coordinates after using Describe to access the information, i.e.:

theExtentRaster = clip.tif

theDesc = arcpy.Describe(theExtentRaster)

theExtent = theDesc.extent

theExtentString = str(theExtent.XMin) + ' ' + str(theExtent.YMin) + ' ' + str(theExtent.XMax) + ' ' + str(theExtent.YMax)

I get this error: ExecuteError: ERROR 000622: Failed to execute (Clip). Parameters are not valid. ERROR 000628: Cannot set input into parameter rectangle.

I also tried adding single quotes or double quotes to theExtentString.

So, again, it isn't accessing the information, (I even tried the code snippet in the Extent page you referenced), it is FORMATTING the four coordinates in a way the arcpy.Clip_management command will accept.

Any ideas? Thanks, Darlene

Re: how to enter 'rectangle' argument in raster Clip

NeilAyres — Thu, 08 Sep 2016 14:44:07 GMT

Try this :

ExtStr = "{} {} {} {}".format(XMin, YMin, XMax, YMax)‍

Re: how to enter 'rectangle' argument in raster Clip

DarleneWilcox — Thu, 08 Sep 2016 15:01:26 GMT

Neil Ayres ... you rock! That worked -- yeah!

Do you know where (other than right here!) this is documented? -- no joke when I say I spent all day yesterday trying every thing I could think of and searching all over the forums and stack exchange and so on.

Again -- THANK YOU!!!!!

Re: how to enter 'rectangle' argument in raster Clip

NeilAyres — Thu, 08 Sep 2016 18:55:47 GMT

It's just that adding strings to other strings with other strings and all the extra quotes etc, sometimes get very confusing.

the "{Var1} {Var2} {Var3}".format(x, y, z) syntax is much clearer.

Glad it worked for you.

Re: how to enter 'rectangle' argument in raster Clip

DanPatterson_Retired — Thu, 08 Sep 2016 19:50:22 GMT

Darlene

I have written a couple of blogs on formating in python and numpy... here is one of several

/blogs/dan_patterson/2016/03/01/basic-fancy-formats