Creating fishnet from template feature class using ArcPy?

Question

I can’t use the tool arcpy.CreateFishnet_management because define the parameter “templateExtent” with a shapefile it is not filling automatically the parameters “originCoordinate” and “yAxisCoordinate”.

import arcpy
from arcpy import env
env.overwriteOutput = True
env.workspace = r"D:\Users\julia\erste_aufg"

#Process: Create Fishnet
outFeatureClass = r"D:\Users\julia\erste_aufg\at001l_wien\at001l_wien\wien.shp"
cellSizeWidth = '200'
cellSizeHeight = '200'
templateExtent = r"D:\Users\julia\erste_aufg\at001l_wien\at001l_wien\at001l_wien.shp"

arcpy.CreateFishnet_management(outFeatureClass, "", "", cellSizeWidth, cellSizeHeight, '0', '0', "", "NO_LABELS", templateExtent, "POLYGON")

It is working in the ModelBulider, so something is running in the background of the ModelBulider that it could create the parameters “originCoordinate” and “yAxisCoordinate” when it has a “templateExtent”. How can I get this tool running in ArcPy by having just the parameter “templateExtent”?

I would be really happy if someone has a solution because I need the Fishnet in a scripttool and cannot go one without because in the end there is a loop so the values of the extent are always different. the first part of the whole script

Answer 1

here is an example. You need to extract the bounding box from a describe object.

desc = arcpy.Describe(fc)
arcpy.CreateFishnet_management(fc[:-4]+"_c200.shp",str(desc.extent.lowerLeft),str(desc.extent.XMin) + " " + str(desc.extent.YMax + 10),"200","200","0","0",str(desc.extent.upperRight),"NO_LABELS","#","POLYGON")

Answer 2

Here is an alternate approach that I used to create multiple fishnets within the extents of each feature within a feature class. The search_extents variable defines the path to that feature class defining the extents of each fishnet I wanted to create. There was no rotation of the fishnet.

search_extents = "path to extents" 
rows = arcpy.SearchCursor(search_extents)
shapeName = arcpy.Describe(search_extents).shapeFieldName
for row in rows:
    print("Starting Extent" + row.getValue("Extent_Num"))
    feat = row.getValue(shapeName)
    extent = feat.extent
    arcpy.CreateFishnet_management(arcpy.env.workspace + "/extents/extentgrid" + row.getValue("Extent_Num"),str(extent.lowerLeft), str(extent.upperLeft),"0","0","200","200",str(extent.upperRight),"NO_LABELS","#","POLYGON")
    print("Finishing Extent" + row.getValue("Extent_Num"))

Answer 3

Here is the code that I finally successfully got working (with help from the examples above) to solve the problem described here:

    env.workspace = "C:/Holly/Work/Projects/NavigationStudy2019/Data"

    # Fetch each feature from the cursor and examine the extent properties
    for row in arcpy.da.SearchCursor(feature_class, ['SHAPE@', 'id']):
        extent = row[0].extent
        print('Extent of home range {}:'.format(row[1]))
        print('XMin: {}, YMin: {}'.format(extent.XMin, extent.YMin))
        print('XMax: {}, YMax: {}'.format(extent.XMax, extent.YMax))
        arcpy.CreateFishnet_management("fishnet_temp.shp",
                                       str(extent.XMin) + " " + str(extent.YMax),
                                       str(extent.XMin) + " " + str(extent.YMax + 10),
                                       "100",
                                       "100",
                                       "",
                                       "",
                                       "",
                                       "LABELS",
                                       feature_class,
                                       "POLYGON")