Polygon from GeoJson to Shp conversion arcpy script is being simplified

MattEiben — Mon, 13 Jan 2014 20:51:59 GMT

I'm trying to make a script that converts the GeoJson format into a shapefile. For the most part, the script in complete, but I'm having an odd issue with the output polygon.

The JSON geometry has a large number of vertices, but ArcMap seem to be GREATLY simplifying the output polygon when arcpy.Polygon(arcpy.Array(point, point, point ...)) happens.

The script I'm using is posted below. Though note, I left out many of the not relevant parts.

from collections import OrderedDict import arcpy, json, os  arcpy.env.overwriteOutput = True  def createPolygon(data):     """     This function receives a python dictionary representing the JSON array and its geometry     type.  It will create a feature class of that geometry type and add in the features geometry     and attributes (if any).     """      # Create feature class and define as WGS84     outFC = arcpy.CreateFeatureclass_management(outLocation,outName,"POLYGON")     arcpy.DefineProjection_management(outFC, coordinateSystem)          features = data["features"]          # Get a list of fields and add them to the feature class     fields = [key for key, value in features[0]["properties"].iteritems()]          if len(fields) != 0:         # dummyField is used because ArcMap requires at least one non-required field.         arcpy.AddField_management(outFC,"dummyField","TEXT")         arcpy.DeleteField_management(outFC,"Id")         for field in fields:             arcpy.AddField_management(outFC,field,"TEXT")         arcpy.DeleteField_management(outFC,"dummyField")          # Create search cursor     cursor = arcpy.da.InsertCursor(outFC, ["SHAPE@"] + fields)          #Create Arcpy Array to add Polygon verticies too.     array = arcpy.Array()      # Building Polygon     n = 0     for feature in features:          n += 1                  for geom in feature["geometry"]["coordinates"]:             for coords in geom:                 # Adding verticies to array                 array.add(arcpy.Point( float(coords[0]), float(coords[1]) ))                          # Get attributes for insert cursor fields         attributes = [attr for key, attr in feature["properties"].iteritems()]                  # Some debugging prints           print len(array)                            # this reads 150 arcpy.Point objects         print arcpy.Polygon(array).pointCount       # This only reads 15 points, none of which are the original points.  Somehow ArcMap is GREATLY simplifyig this geometry.                  cursor.insertRow([arcpy.Polygon(array)] + attributes)         array.removeAll()          del cursor         jsonFileName = "inputjsonfile.json" shpOutput = "C:\Path\To\Output\Location\polygon.shp"  outLocation = os.path.dirname(shpOutput) outName = os.path.basename(shpOutput)  coordinateSystem = arcpy.SpatialReference(4326)  with open(jsonFileName,"r") as json_file:     data = json.load(json_file, object_pairs_hook=OrderedDict)          # Get geometry type     geomType = data["features"][0]["geometry"]["type"]      if geomType == "Polygon":         createPolygon(data)

The inputs and outputs have been hardcoded for this example, but eventually it will end up as a Python Toolbox

For testing purposes, below is the JSON file I was trying to convert in this example:

{"type": "FeatureCollection", "features": [{"type": "Feature", "properties": {"Id": "0", "NAME": "Untitled Polygon", "DESCR": " ", "FOLDER": " "}, "geometry": {"bbox": [-105.6266922454426, 33.309856365277824, -105.61766863755298, 33.31951402483418], "coordinates": [[["-105.623511", "33.317474"], ["-105.623508", "33.317525"], ["-105.623477", "33.317550"], ["-105.623410", "33.317651"], ["-105.623255", "33.317725"], ["-105.623129", "33.317825"], ["-105.623035", "33.317875"], ["-105.622915", "33.317873"], ["-105.622794", "33.317871"], ["-105.622647", "33.317792"], ["-105.622592", "33.317715"], ["-105.622505", "33.317612"], ["-105.622352", "33.317536"], ["-105.622136", "33.317434"], ["-105.622015", "33.317357"], ["-105.621831", "33.317304"], ["-105.621673", "33.317253"], ["-105.621551", "33.317226"], ["-105.621368", "33.317174"], ["-105.621337", "33.317173"], ["-105.621242", "33.317223"], ["-105.621115", "33.317298"], ["-105.621108", "33.317450"], ["-105.621133", "33.317578"], ["-105.621186", "33.317732"], ["-105.621241", "33.317861"], ["-105.621356", "33.318016"], ["-105.621381", "33.318119"], ["-105.621464", "33.318275"], ["-105.621482", "33.318507"], ["-105.621507", "33.318610"], ["-105.621497", "33.318791"], ["-105.621424", "33.318972"], ["-105.621257", "33.319179"], ["-105.621129", "33.319230"], ["-105.620967", "33.319334"], ["-105.620837", "33.319411"], ["-105.620739", "33.319489"], ["-105.620644", "33.319514"], ["-105.620457", "33.319512"], ["-105.620182", "33.319507"], ["-105.619851", "33.319423"], ["-105.619417", "33.319278"], ["-105.619082", "33.319195"], ["-105.618724", "33.319046"], ["-105.618416", "33.318900"], ["-105.618238", "33.318741"], ["-105.618051", "33.318500"], ["-105.617920", "33.318313"], ["-105.617896", "33.318209"], ["-105.617900", "33.318081"], ["-105.617877", "33.317926"], ["-105.617718", "33.317613"], ["-105.617669", "33.317381"], ["-105.617673", "33.317152"], ["-105.617674", "33.316846"], ["-105.617685", "33.316565"], ["-105.617703", "33.316411"], ["-105.617751", "33.316283"], ["-105.617761", "33.316181"], ["-105.617843", "33.315979"], ["-105.617887", "33.315878"], ["-105.617963", "33.315777"], ["-105.618075", "33.315652"], ["-105.618192", "33.315553"], ["-105.618349", "33.315406"], ["-105.618570", "33.315260"], ["-105.618872", "33.315167"], ["-105.619245", "33.315051"], ["-105.619605", "33.314985"], ["-105.619946", "33.314869"], ["-105.620061", "33.314845"], ["-105.620328", "33.314726"], ["-105.620592", "33.314631"], ["-105.620778", "33.314487"], ["-105.621017", "33.314367"], ["-105.621149", "33.314248"], ["-105.621169", "33.314104"], ["-105.621163", "33.313937"], ["-105.621128", "33.313771"], ["-105.621072", "33.313558"], ["-105.620928", "33.313370"], ["-105.620776", "33.313155"], ["-105.620615", "33.312986"], ["-105.620475", "33.312766"], ["-105.620310", "33.312694"], ["-105.620201", "33.312646"], ["-105.620090", "33.312573"], ["-105.619838", "33.312450"], ["-105.619617", "33.312304"], ["-105.619412", "33.312105"], ["-105.619183", "33.311882"], ["-105.619016", "33.311614"], ["-105.618821", "33.311273"], ["-105.618801", "33.311131"], ["-105.618895", "33.310834"], ["-105.619041", "33.310570"], ["-105.619432", "33.310313"], ["-105.619758", "33.310103"], ["-105.620176", "33.309952"], ["-105.620624", "33.309856"], ["-105.621002", "33.309897"], ["-105.621464", "33.309992"], ["-105.621709", "33.310086"], ["-105.621857", "33.310213"], ["-105.621952", "33.310367"], ["-105.621971", "33.310478"], ["-105.622093", "33.310607"], ["-105.622246", "33.310834"], ["-105.622495", "33.311170"], ["-105.622773", "33.311533"], ["-105.622925", "33.311762"], ["-105.623194", "33.312341"], ["-105.623289", "33.312598"], ["-105.623422", "33.312690"], ["-105.623501", "33.312759"], ["-105.623716", "33.312825"], ["-105.623853", "33.312845"], ["-105.623964", "33.312868"], ["-105.624024", "33.312869"], ["-105.624166", "33.312943"], ["-105.624244", "33.313062"], ["-105.624417", "33.313212"], ["-105.624569", "33.313244"], ["-105.624833", "33.313324"], ["-105.625213", "33.313455"], ["-105.625559", "33.313582"], ["-105.625844", "33.313705"], ["-105.625987", "33.313779"], ["-105.626188", "33.313878"], ["-105.626360", "33.313976"], ["-105.626472", "33.314123"], ["-105.626612", "33.314319"], ["-105.626692", "33.314538"], ["-105.626684", "33.314782"], ["-105.626677", "33.315003"], ["-105.626641", "33.315224"], ["-105.626548", "33.315396"], ["-105.626513", "33.315569"], ["-105.626420", "33.315741"], ["-105.625983", "33.316182"], ["-105.625570", "33.316456"], ["-105.625347", "33.316607"], ["-105.625094", "33.316757"], ["-105.624817", "33.316904"], ["-105.624307", "33.317195"], ["-105.624008", "33.317363"], ["-105.623802", "33.317433"], ["-105.623655", "33.317479"], ["-105.623511", "33.317474"]]], "type": "Polygon"}}]}

Any help is appreciated,
Thanks!

Matt

Re: Polygon from GeoJson to Shp conversion arcpy script is being simplified

StacyRendall1 — Mon, 13 Jan 2014 22:04:25 GMT

Hi Matt,

If you specify the coordinate system when creating the polygons (lines 51 and 53 of your original code) it appears to work...

        print arcpy.Polygon(array, coordinateSystem).pointCount          cursor.insertRow([arcpy.Polygon(array, coordinateSystem)] + attributes)

Let me know how you get on.

Stacy

Re: Polygon from GeoJson to Shp conversion arcpy script is being simplified

MattEiben — Mon, 13 Jan 2014 22:11:43 GMT

That did it!

I didn't see the inputs for the Polygon object:

Polygon (inputs, {spatial_reference}, {has_z}, {has_m})

Putting the spatial reference in there worked like a charm,
Thanks very much!

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Polygon from GeoJson to Shp conversion arcpy script is being simplified

Re: Polygon from GeoJson to Shp conversion arcpy script is being simplified

Re: Polygon from GeoJson to Shp conversion arcpy script is being simplified