ArcMap – Performing Reverse Clip

arcgis-desktoparcmapbufferclippolygon

Is there a way to perform a 'reverse' of the clip function in ArcMap?

I am not exactly sure how to explain this so here is a diagram:

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Best Answer

Use the Erase (Analysis) Tool:

enter image description here

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[GIS] Scripting a Loop of Clip (Analysis)

You can use Python's built-in .split() to extract that part of the name:

file = "WVHGT_201403281200_f180_201404050000.shp"
name = file.split("_")
print name[2]

>>>
f180

Now, integrate this into the for loop. I am assuming you are iterating through a collection of files rather than individual features.

import arcpy, os
from arcpy import env

env.workspace = r"C:\temp1"
outws = r"C:\temp2"

clip_features = r"C:\temp\clipper.shp"

fcs = arcpy.ListFeatureClasses()

for fc in fcs:
    name = fc.split("_")[2] # Extract part of the name
    out_feature_class = os.path.join(outws, name)  # Combine out workspace and filename 
    # Execute Clip
    arcpy.Clip_analysis(fc, clip_features, out_feature_class)

Reverse Clipping (Erasing) Techniques in R

Seems to be a simple application of gDifference from the rgeos package:

> require(rgeos)
> ukhole = gDifference(uk, lnd)
Warning message:
In RGEOSBinTopoFunc(spgeom1, spgeom2, byid, id, "rgeos_difference") :
  spgeom1 and spgeom2 have different proj4 strings
> plot(ukhole)

The projection warning is because the LondonBoroughs shapefile doesn't have a .prj file.

Just to make sure that's a hole and not an outline or another solid polygon:

> gArea(lnd) + gArea(ukhole) - gArea(uk)
[1] 0

Best Answer

Related Solutions

[GIS] Scripting a Loop of Clip (Analysis)

Reverse Clipping (Erasing) Techniques in R

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