[GIS] Split Multiple Polygons into equal squares

arcgis-desktoparcmapbatchsplitting

I have 1 single shapefile of about 70k square polygons in a grid. I want to run a process/tool/script to split all 70k polygons into 4 equal parts. The polygons are contiguous, so each polygon only has 4 vertices. Basically I have a shapefile of sections for a sate, and I want to split it into 1/4 sections so each original square section is broken into 4 equal 1/4 parts.

How can I split all 70,000 contiguous square polygons at once with only 4 vertices each into 4 equal parts to create 4 polygons within each original polygon?

Best Answer

Assuming your polygon dataset is a regular grid of polygons, rather than square polygons randomly placed everywhere then this can be achieved with a simple model to create a fishnet then retrospectively delete out the polygons you do not need.

The model to achieve this is this:

Here is final output applied to the original grid (red outlines):

Related Solutions

[GIS] How to split a polygon into quadrants

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.

[GIS] Automate Splitting Polygons Into Sections

Here is a method using arcpy geometry objects. The script creates a rotated hull rectangle around each polygon, splits it into plots, and clips the plots to the original polygon. As Aaron mentions, you could likely achieve this with the fishnet tool, but I could not figure out how to (in Step #2) "use logic to find the ordinal coords" for rotated polygons.

The script:

# import libraries
import arcpy

# set input/output parameters
polyFC = arcpy.GetParameterAsText(0)        # input polygons
# standalone: polyFC = r'C:/somefolder/someshapefile.shp'
outSections = arcpy.GetParameterAsText(1)   # output section polygons
# standalone: outSections = r'C:/somefolder/someshapefile.shp'

# establish spatial reference
desc = arcpy.Describe(polyFC)
SR = desc.spatialReference

# lines container
Lines = []

for row in arcpy.da.SearchCursor(polyFC, ["SHAPE@"]):
    # create hull rectangle to establish a rotated area of interest
    coordSplit = row[0].hullRectangle.split(' ')

    # collect corner coordinates
    coordList = arcpy.Array([arcpy.Point(coordSplit[0],coordSplit[1]),arcpy.Point(coordSplit[2],coordSplit[3]),arcpy.Point(coordSplit[4],coordSplit[5]),arcpy.Point(coordSplit[6],coordSplit[7]),arcpy.Point(coordSplit[0],coordSplit[1])])

    # create lines from hull rectangle
    currentLines = []
    for pointNum in range(0,4):
        arcpy.Array([coordList.getObject(pointNum),coordList.getObject(pointNum+1)])
        hullRecLine = arcpy.Polyline(arcpy.Array([coordList.getObject(pointNum),coordList.getObject(pointNum+1)]))
        currentLines.append(hullRecLine)

    # compare first and second line to determine if first line is short or long
    firstLong = 0
    if currentLines[0].length > currentLines[1].length:
        firstLong = 1

    # determine how far apart to split lines
    longLineSpace = currentLines[firstLong].length/4
    shortLineSpace = currentLines[firstLong + 1].length/2

    # join points to create parallel lines
    for point in range(1,4):
        longPoint1 = currentLines[firstLong].positionAlongLine(longLineSpace*point)
        longPoint2 = currentLines[firstLong + 2].positionAlongLine(currentLines[firstLong + 2].length - (longLineSpace*point))
        longLine = arcpy.Polyline(arcpy.Array([longPoint1.centroid,longPoint2.centroid]), SR)

        # clip lines to original polygon
        longLineClip = longLine.intersect(row[0],2)
        # add to array
        Lines.append(longLineClip)

    shortPoint1 = currentLines[firstLong + 1].positionAlongLine(shortLineSpace)
    shortPoint2 = currentLines[firstLong - 1].positionAlongLine(currentLines[firstLong - 1].length - (shortLineSpace))
    shortLine = arcpy.Polyline(arcpy.Array([shortPoint1.centroid,shortPoint2.centroid]), SR)

    # clip to original polygon
    shortLineClip = shortLine.intersect(row[0],2)
    # add to array
    Lines.append(shortLineClip)

# write geometries to disk
arcpy.CopyFeatures_management(Lines, outSections)

# add to map
mxd = arcpy.mapping.MapDocument("CURRENT")
dataFrame = arcpy.mapping.ListDataFrames(mxd, "*")[0]
addLayer = arcpy.mapping.Layer(outSections)
arcpy.mapping.AddLayer(dataFrame, addLayer)

del row

And the output: enter image description here

Best Answer

Related Solutions

[GIS] How to split a polygon into quadrants

[GIS] Automate Splitting Polygons Into Sections

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