[GIS] How to split a polygon into quadrants

arcgis-desktoppolygon-creationtownship-range-sectionvector-grid

I have a Alberta province (Canada) section polygon shapefile in GCS_NAD83 with 255,000 polygons. I like to split each section into 4 equal quadrants (NW, NE, SW, SE)

enter image description here

The Alberta province has several UTM zones, so I guess I can convert it to Lambert Conformal Conic or Albers Equal Area CS if the section scan be split only in projected units.
There are people selling this information, but I was wondering if this is something I can create using the data I have?
Please let me know. Thank you.

Best Answer

I've created 4 tools which might help you out.

1) The first 2 tools create a quarter section grid from an existing section grid and provide custom labeling for each quarter section.

2) The other 2 tools create a quarter quarter section grid from an existing section grid and provide custom labeling for each quarter quarter section.

I say from an existing section grid, but it will work with any polygon grid.

You can view a video (which needs updated) and download the Section Grid Toolbox here:

http://ianbroad.com/creating-quarter-quarter-section-grid-python/

I hope this helps in some way.

Related Solutions

[GIS] How to split a polygon into multiple small parts by grid

Here is what you can do:

If your grid is a raster convert it to a polygon feature class (fc)
Use the Split tool (or ET GeoWizard Split by Location tool) to create multiple fc by the split attribute
Use Merge tool to merge mutiple fc to one fc

[GIS] How to split circles in 8 quadrants

I've written a script for 10.1/10.2, however you might see if it is possible to rewrite it for 9.3. I've almost never used arcgisscripting, but I guess it would be hard to implement the same without arcpy in 10.0+. Bearing Distance To Line GP tool I've used is available only in 10.0+, too.

If 9.3 is your only option, you could try to generate the lines with arcgisscripting in 9.3 (with the same logic as I've used with arcpy in the code below) and then use ET Geowizards Partition Polygons with Polylines which works similar to Feature To Polygon GP tool in ArcGIS. Another tool that looks promising is Points To Pie Segments from ET Geowizards.

If you will be able to get 10.1+ via evaluation license or if you upgrade, then you could use this script. All other users who find this post and are on 10.1+ could also benefit from using this script. This script assumes your source points you've used for buffering represent the centroid of the output buffer circles.

import arcpy, math

arcpy.env.overwriteOutput = True
arcpy.env.workspace = r"C:\GIS\Temp\test.gdb"
tempworkspace = arcpy.env.workspace
in_poly_fc = r"C:\GIS\Temp\test.gdb\CirclesFeatureClass"
clip_lines_fc = r"ClipLines"
sum_lines_fc = r"SumClipLines"

#converting an existing fc with circles to Geometry objects
geometries = arcpy.CopyFeatures_management(in_poly_fc,arcpy.Geometry())

for feature in geometries:
    #obtaining a centroid of the circle centroid via Geometry class attribute
    centroid_Point = feature.trueCentroid
    centroid_xy = []

    #obtaining XY coordinates of the centroid via Point class attribute
    centroid_xy.append(centroid_Point.X)
    centroid_xy.append(centroid_Point.Y)

    #obtaining the radius
    #have to add a small overhead value to make sure the radius end point will overshoot the polygon
    #otherwise may get undershooting lines which depends on the precision of the coordinates
    #and XY tolerance of the source data
    radius = math.sqrt(feature.area / math.pi) + 1

    #supply the list of angles for bearing
    bearing_angles = [0,45,90,135,180,225,270,315,360]

    #creating bearing angles table and adding fields
    bearing_table = arcpy.CreateTable_management(tempworkspace,"BearingDataTable")
    arcpy.AddField_management(bearing_table,"Xcoord","Double")
    arcpy.AddField_management(bearing_table,"Ycoord","Double")
    arcpy.AddField_management(bearing_table,"Bearing","Double")
    arcpy.AddField_management(bearing_table,"Distance","Double")

    #inserting all required lines constructed from centroid with the radius and bearing angle
    with arcpy.da.InsertCursor(bearing_table,["Xcoord","Ycoord","Bearing","Distance"]) as ins_cursor:
        for bearing_angle in bearing_angles:
            ins_cursor.insertRow((centroid_xy[0],centroid_xy[1],bearing_angle,radius))
    del ins_cursor

    #projected coordinate system used for output lines feature classes generated
    project_coordsys = """PROJCS['NAD_1927_StatePlane_Alabama_East_FIPS_0101',GEOGCS['GCS_North_American_1927',
    DATUM['D_North_American_1927',SPHEROID['Clarke_1866',6378206.4,294.9786982]],PRIMEM['Greenwich',0.0],
    UNIT['Degree',0.0174532925199433]],PROJECTION['Transverse_Mercator'],PARAMETER['False_Easting',500000.0],
    PARAMETER['False_Northing',0.0],PARAMETER['Central_Meridian',-85.83333333333333],
    PARAMETER['Scale_Factor',0.99996],PARAMETER['Latitude_Of_Origin',30.5],
    UNIT['Foot_US',0.3048006096012192]];-17948200 -43887100 3048,00609601219;
    -100000 10000;-100000 10000;3,28083333333333E-03;0,001;0,001;IsHighPrecision"""

    arcpy.BearingDistanceToLine_management(bearing_table,clip_lines_fc,"Xcoord","Ycoord",
                                           "Distance","Feet","Bearing",spatial_reference=project_coordsys)
    #adding each circle's 8 lines in iteration to the sum output line feature class
    arcpy.Append_management(clip_lines_fc,sum_lines_fc,"NO_TEST")

    #deleting temp feature classes to avoid locking issues at next iteration
    arcpy.Delete_management(bearing_table)
    arcpy.Delete_management(clip_lines_fc)

#cutting each circle in the polygon feature class by using the lines obtained earlier
arcpy.FeatureToPolygon_management([in_poly_fc,sum_lines_fc],"Quadrants","#","ATTRIBUTES","#")

The source polygon feature class with circles:

enter image description here

The processed circles, each divided into 8 segments:

enter image description here

Best Answer

Related Solutions

[GIS] How to split a polygon into multiple small parts by grid

[GIS] How to split circles in 8 quadrants

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