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Using Fishnet to Create 4-quarters of polygon, but fishnet is not rotating. Help please.

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3
06-15-2023 02:08 PM
NathanBaier1
Occasional Contributor

Hi, I have been working on the code below and it is working, but the fishnet is square to the input polygon and does not follow the angle of the input polygon. I need the fishnets to be angled with the input polygons so the fishnet grid aligns the input polygon grid. 

import arcpy
import os
import os, fnmatch, arcpy
from arcpy import env
env.workspace = r"C:\GIS\Projects\TetonRange\Geoprocesing.gdb"
env.overwriteOutput = True

fc = arcpy.GetParameterAsText(0)
output = arcpy.GetParameterAsText(1)

rows = arcpy.SearchCursor(fc)
for row in rows:
x = row.OBJECTID
arcpy.MakeFeatureLayer_management(fc, "fc_lyr", "OBJECTID = " + str(x))
rows2 = arcpy.SearchCursor("fc_lyr")
for row2 in rows2:
XMIN = row2.shape.extent.XMin
YMIN = row2.shape.extent.YMin
XMAX = row2.shape.extent.XMax
YMAX = row2.shape.extent.YMax
YMIN2 = row2.shape.extent.YMin + 10
orig_coord = str(XMIN) + " " + str(YMIN)
y_axis = str(XMIN) + " " + str(YMIN2)
corner_coord = str(XMAX) + " " + str(YMAX)

arcpy.CreateFishnet_management("Fishnet_" + str(x), orig_coord, y_axis, "0", "0", "2", "2", corner_coord, "NO_LABELS", "", "POLYGON")
#arcpy.analysis.Intersect("Fishnet_"+str(x) ; "fc_lyr","clip_"+str(x)), "ALL". None, "Input")
arcpy.Clip_analysis("Fishnet_"+str(x), "fc_lyr","clip_"+str(x))

del row, rows, row2, rows2


mergeList = arcpy.ListFeatureClasses("clip_*")
arcpy.Merge_management(mergeList, "merge_poly")

arcpy.AddField_management("merge_poly","ACRES","Double")
arcpy.management.DefineProjection("merge_poly", 'GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]')
arcpy.analysis.Intersect([fc,"merge_poly"], output, "ALL", None, "INPUT")
arcpy.management.CalculateGeometryAttributes(output, "ACRES AREA_GEODESIC", '', "ACRES_US", 'GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]', "SAME_AS_INPUT")
#arcpy.management.DeleteField(output, "FID_OK_sections1_test;OBJECTID;Shape_Leng;FID_merge_poly", "DELETE_FIELDS")

# Create a new field called "Quarter" in the fishnet grid feature class
#quarter_name = "Quarter"
arcpy.AddField_management(output, "Quarter", "TEXT", field_length=2)

# Update the "Quarter" field for each fishnet polygon
with arcpy.da.UpdateCursor(output, ["SHAPE@", "Quarter"]) as cursor:
for row in cursor:
fishnet_polygon = row[0]
quarter = ""

# Get the centroid of the fishnet polygon
fishnet_centroid = fishnet_polygon.centroid

# Iterate through each original polygon
with arcpy.da.SearchCursor(fc, ["SHAPE@"]) as poly_cursor:
for poly_row in poly_cursor:
original_polygon = poly_row[0]

# Compare the centroid of the original polygon with the fishnet centroid
if original_polygon.contains(fishnet_centroid):
# Determine the quarter based on the spatial location
if fishnet_centroid.X < original_polygon.centroid.X:
if fishnet_centroid.Y < original_polygon.centroid.Y:
quarter = "SW"
else:
quarter = "NW"
else:
if fishnet_centroid.Y < original_polygon.centroid.Y:
quarter = "SE"
else:
quarter = "NE"

break # Exit the loop if a match is found

# Update the "Quarter" field
row[1] = quarter
cursor.updateRow(row)
delete_identical_rows = arcpy.management.DeleteIdentical(output, ["FRSTDIVID","Quarter"])

print("Quarter field populated successfully.")

print("Complete")

 

 

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3 Replies
DanPatterson
MVP Esteemed Contributor

Code formatting ... the Community Version - Esri Community

will provide proper formatting and line numbers for reference


... sort of retired...
DanPatterson
MVP Esteemed Contributor

Perhaps the following, but you had better check the indentation logic... I was beginning to lose its focus

 

import arcpy
import os
import os, fnmatch, arcpy
from arcpy import env
env.workspace = r"C:\GIS\Projects\TetonRange\Geoprocesing.gdb"
env.overwriteOutput = True
fc = arcpy.GetParameterAsText(0)
output = arcpy.GetParameterAsText(1)

rows = arcpy.SearchCursor(fc)
for row in rows:
    x = row.OBJECTID
    arcpy.MakeFeatureLayer_management(
        fc,
        "fc_lyr",
        "OBJECTID = " + str(x)
    )
    rows2 = arcpy.SearchCursor("fc_lyr")
    for row2 in rows2:
        XMIN = row2.shape.extent.XMin
        YMIN = row2.shape.extent.YMin
        XMAX = row2.shape.extent.XMax
        YMAX = row2.shape.extent.YMax
        YMIN2 = row2.shape.extent.YMin + 10
        orig_coord = str(XMIN) + " " + str(YMIN)
        y_axis = str(XMIN) + " " + str(YMIN2)
        corner_coord = str(XMAX) + " " + str(YMAX)

        arcpy.CreateFishnet_management(
            "Fishnet_" + str(x),
            orig_coord, y_axis,
            "0", "0", "2", "2",
            corner_coord,
            "NO_LABELS",
            "",
            "POLYGON"
        )
        # arcpy.analysis.Intersect("Fishnet_"+str(x) ; "fc_lyr","clip_"+str(x)), "ALL". None, "Input")
        arcpy.Clip_analysis(
            "Fishnet_" + str(x),
            "fc_lyr",
            "clip_" + str(x)
        )

del row, rows, row2, rows2


mergeList = arcpy.ListFeatureClasses("clip_*")
arcpy.Merge_management(mergeList, "merge_poly")

arcpy.AddField_management("merge_poly", "ACRES", "Double")
# -- substitute the 2nd parameter below with thecoordinate system factory code
arcpy.management.DefineProjection(
    "merge_poly",
    'GEOGCS["GCS_North_American_1983", DATUM["D_North_American_1983", SPHEROID["GRS_1980", 6378137.0, 298.257222101]], PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]'
)
arcpy.analysis.Intersect(
    [fc,"merge_poly"], output, "ALL", None, "INPUT"
)
# -- substitute the last parameter below with thecoordinate system factory code
arcpy.management.CalculateGeometryAttributes(
    output,
    "ACRES AREA_GEODESIC",
    '',
    "ACRES_US",
    'GEOGCS["GCS_North_American_1983", DATUM["D_North_American_1983", SPHEROID["GRS_1980", 6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]', "SAME_AS_INPUT"
)
# arcpy.management.DeleteField(output, "FID_OK_sections1_test;OBJECTID;Shape_Leng;FID_merge_poly", "DELETE_FIELDS")

# Create a new field called "Quarter" in the fishnet grid feature class
#quarter_name = "Quarter"
arcpy.AddField_management(output, "Quarter", "TEXT", field_length=2)

# Update the "Quarter" field for each fishnet polygon
with arcpy.da.UpdateCursor(output, ["SHAPE@", "Quarter"]) as cursor:
    for row in cursor:
        fishnet_polygon = row[0]
        quarter = ""
        # Get the centroid of the fishnet polygon
        fishnet_centroid = fishnet_polygon.centroid

# Iterate through each original polygon
with arcpy.da.SearchCursor(fc, ["SHAPE@"]) as poly_cursor:
    for poly_row in poly_cursor:
        original_polygon = poly_row[0]
        # Compare the original polygon centroid with the fishnet centroid
        if original_polygon.contains(fishnet_centroid):
            # Determine the quarter based on the spatial location
            if fishnet_centroid.X < original_polygon.centroid.X:
                if fishnet_centroid.Y < original_polygon.centroid.Y:
                    quarter = "SW"
                else:
                    quarter = "NW"
            else:
                if fishnet_centroid.Y < original_polygon.centroid.Y:
                    quarter = "SE"
                else:
                    quarter = "NE"
            break  # Exit the loop if a match is found

        # Update the "Quarter" field
        row[1] = quarter
        cursor.updateRow(row)
delete_identical_rows = arcpy.management.DeleteIdentical(output, ["FRSTDIVID", "Quarter"])
print("Quarter field populated successfully.")
print("Complete")

 

  


... sort of retired...
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NathanBaier1
Occasional Contributor

Sorry about that. It got messed up before I inserted the code properly.

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