arcgis-10.2arcgis-desktoppolygonize
I have an issue where I have feature classes of groups of zip codes in different sectors of the US that I have created. I want to be able to define the outer boundary of these groups so I can create a single shape file (one polygon). I was going to use this new polygon to clip the original file.
Is there a way to take many polygons and create a file that only shows the outer extent of the group? And how would I go about such an endeavor?
You might experiment with type of spatial join at 5 because centroid points might fall outside BLANKS. This will fill gaps. No easy solution for outer boundary, sorry
This will convert your polygons into arcs very quickly. You need 2 layers in table of content: 1st - polylines, 2nd - polygons
import arcpy, traceback, os, sys,time
from arcpy import env
env.overwriteOutput = True
dissolved="in_memory/dissolved"
try:
def showPyMessage():
arcpy.AddMessage(str(time.ctime()) + " - " + message)
mxd = arcpy.mapping.MapDocument("CURRENT")
theLinksLayer=arcpy.mapping.ListLayers(mxd)[0]
PGONS=arcpy.mapping.ListLayers(mxd)[1]
arcpy.DeleteFeatures_management(theLinksLayer)
curT = arcpy.da.InsertCursor(theLinksLayer,"SHAPE@")
with arcpy.da.SearchCursor(PGONS, "Shape@") as cursor:
for row in cursor:
feat = row[0].boundary()
curT.insertRow((feat,))
arcpy.Dissolve_management(theLinksLayer, dissolved,"","", "SINGLE_PART")
arcpy.DeleteFeatures_management(theLinksLayer)
m=0
arcpy.AddMessage("Dissolving ...")
curT = arcpy.da.InsertCursor(theLinksLayer,"SHAPE@")
with arcpy.da.SearchCursor(dissolved, "SHAPE@") as cursor:
for row in cursor:
m+=1
curT.insertRow((row[0],))
arcpy.Delete_management("in_memory")
arcpy.RefreshActiveView()
arcpy.AddMessage("\nPolygons unbuilt into %i lines\n" %m)
del curT
except:
message = "\n*** PYTHON ERRORS *** "; showPyMessage()
message = "Python Traceback Info: " + traceback.format_tb(sys.exc_info()[2])[0]; showPyMessage()
message = "Python Error Info: " + str(sys.exc_type)+ ": " + str(sys.exc_value) + "\n"; showPyMessage()
From here it is enough to spatially join lines to polygons (one to many, SHARE_A_LINE_SEGMENT_WITH) and dissolve output using line name and first, last polygon IDs to get this:
Best Answer
In ArcGIS, use the Minimum Bounding Geometry tool. You have several options of which kind of "encompassing" geometry you'd like to get back to clip against. Just remember to use
ALLfor thegroup_optionparameter if you only want one geometry back.EDIT: Based on how I understand what you're asking for now, I think the dissolve tool is more appropriate. Dissolve on the same field that you are using to set up your class breaks.