10.2.x - Getting Data Extents as Feature Classes (4 Methods)

Over the past couple of years, I have posted many posts on creating polygon extents from data.  Today, I am going to provide 4 ways to get the extent of a polygon.

1. Use the 'Minimum Bounding Geometry' tool to create 'ENVELOPE' geometry types with or without the 'Group Option'.  This tool is available at the 'Advanced' level, so if you don't know how to/want to use python, this is your go to option to use.  The output is a feature class.
2. For whole feature class extent use the arcpy.Describe(), and write it out to disk
   

   import arcpy
   from arcpy import env
   env.overwriteOutput = True
   fc = r"c:\States.shp"desc = arcpy.Describe(fc)
   extent = desc.extent
   pts = [arcpy.Point(extent.XMin, extent.YMin),
          arcpy.Point(extent.XMax, extent.YMin),
          arcpy.Point(extent.XMax, extent.YMax),
          arcpy.Point(extent.XMin, extent.YMax)]
   array = arcpy.Array(items=pts)
   poly = arcpy.Polygon(array)
   
   arcpy.CopyFeatures_management(poly, r"%scratchgdb%\way1")
   

3. Method 1 for individual features: Use a cursor with extent XMin, YMin, XMax, and YMax, and arcpy.CreateFeatureClass()
   

   import arcpy
   from arcpy import env
   env.overwriteOutput = True
   fc = r"c:\States.shp"
   out_fc = r"%scratchgdb%\way2"
   if not arcpy.Exists(out_fc):
       arcpy.CreateFeatureclass_management(out_path="%scratchgdb%",
                                           out_name="way2", geometry_type="POLYGON",
                                           spatial_reference=arcpy.SpatialReference(4326))
   icur = arcpy.da.InsertCursor(out_fc, "SHAPE@")
   with arcpy.da.SearchCursor(fc, "SHAPE@") as rows:
       for row in rows:
           extent = row[0].extent
           pts = [arcpy.Point(extent.XMin, extent.YMin),
                  arcpy.Point(extent.XMax, extent.YMin),
                  arcpy.Point(extent.XMax, extent.YMax),
                  arcpy.Point(extent.XMin, extent.YMax)]
           array = arcpy.Array(items=pts)
           poly = arcpy.Polygon(array)
           icur.insertRow([poly])
           del array
           del poly
           del pts
           del extent
           del row
   

4. Method 2 for individual features: Use a cursor objects and arcpy.CopyFeatures()
   

   import arcpy
   from arcpy import env
   env.overwriteOutput = True
   fc = r"c:\States.shp"
   out_fc = r"%scratchgdb%\way3"
   with arcpy.da.SearchCursor(fc, "SHAPE@") as rows:
       polys = []
       array = arcpy.Array()    
       for row in rows:
           extent = row[0].extent
           array.add(extent.lowerLeft)
           array.add(extent.lowerRight)
           array.add(extent.upperRight)
           array.add(extent.upperLeft)
           array.add(extent.lowerLeft)
           polys.append(arcpy.Polygon(array))
           array.removeAll()
           del row
       del array
       arcpy.CopyFeatures_management(polys, out_fc)
       del polys
   

Here are 4 examples on how to create extents using python or the built in system tools in ArcToolbox.
 Enjoy

Population and Water Tackled on NPR's Talk of the Nation

An interesting segment was played on Talk of the Nation yesterday about population growth, water, and food.  As a geographer and someone who is interested in have a sustainable environment, I feel it's worth taking a look at: http://www.npr.org/2011/12/12/143587133/as-global-population-grows-water-matters-more

Enjoy