topic Re: cannot view the shapeFile generated from points in Python Questions

cannot view the shapeFile generated from points

mokamuralidhar — Fri, 02 Feb 2024 21:01:35 GMT

Hi,

I am trying to generate a shape file out of pointFile.

The pointFile has 5 records in it, each records is a point.

it has 5 columns for each records, id,ShapeID,x,y,z. id and shapeID doesn't mean anything.

All these points form a polygon as you can see, the first record is same as the last

record.

Program: I wrote a python program that will read the pointFile and outputs a shapeFile.

There are two methods in it, 1) _create_polyline_shapefile 2) _create_polygon_shapefile

_create_polyline_shapefile will read the points and outputs a Line File.

_create_polygon_shapefile will read the points and outputs a Polygon File.

Problem: what we are facing is the output of _create_polyline_shapefile does not show graphics in ArcMap or ArcScene.

while the one created by first methods displays. The shape file can be viewed in ArcScene for 3dView or ArcMap for 2D view.

looking for a solution for this.

Here are 5 records of the in the PointFile

======================

id, shapeId, x, y, z
1,1,2197490.3821680555,1.5003079009938888E7,1573.2872741540364
2,2,2197478.7284111492,1.5003076194199622E7,1570.29
3,3,2197459.2878189506,1.500307149703293E7,1570.29
4,4,2197446.2932236306,1.5003068357325058E7,1573.6321294959107
5,5,2197490.3821680555,1.5003079009938888E7,1573.2872741540364

Here is the python program

===================

import arcpy
import os

class TextToShapefileConverter:
def __init__(self, input_directory, output_directory, spatial_reference_id=26914😞
self.input_directory = input_directory
self.output_directory = output_directory
self.spatial_reference_id = spatial_reference_id
self.spatial_reference = arcpy.SpatialReference(self.spatial_reference_id)

def convert(self, point_file_name):
input_text_file = os.path.join(self.input_directory, point_file_name)
output_shapefile_name = os.path.splitext(point_file_name)[0] + '.shp'
output_shapefile = os.path.join(self.output_directory, output_shapefile_name)

print "generating", output_shapefile_name

if "PolygonPointFile" in point_file_name:
self._create_polyline_shapefile(output_shapefile, input_text_file)
# self._create_polygon_shapefile(output_shapefile, input_text_file)

def _create_polyline_shapefile(self, output_shapefile, input_text_file):
arcpy.env.overwriteOutput = True
arcpy.CreateFeatureclass_management(
os.path.dirname(output_shapefile),
os.path.basename(output_shapefile),
"POLYLINE", has_z="ENABLED", has_m="DISABLED",
spatial_reference=self.spatial_reference)
arcpy.AddField_management(output_shapefile, "PairID", "LONG")

cursor = arcpy.da.InsertCursor(output_shapefile, ['SHAPE@', 'PairID'])
points = []
pair_id = 0

with open(input_text_file, 'r') as file:
next(file) # Skip header
for line in file:
if line.strip():
_, _, x, y, z = line.split(',')
point = arcpy.Point(float(x), float(y), float(z))
points.append(point)

# Check if a pair of points has been added
if len(points) == 5:
print points
polyline = arcpy.Polyline(arcpy.Array(points), self.spatial_reference, True)
cursor.insertRow([polyline, pair_id])
points = [] # Reset for next pair
pair_id += 1

del cursor

def _create_polygon_shapefile(self, output_shapefile, input_text_file):
arcpy.env.overwriteOutput = True
arcpy.CreateFeatureclass_management(
os.path.dirname(output_shapefile),
os.path.basename(output_shapefile),
"POLYGON", has_z="ENABLED", has_m="DISABLED",
spatial_reference=self.spatial_reference)
arcpy.AddField_management(output_shapefile, "GroupID", "LONG")

cursor = arcpy.da.InsertCursor(output_shapefile, ['SHAPE@', 'GroupID'])
points = []
group_id = 0

with open(input_text_file, 'r') as file:
next(file) # Skip header
for line in file:
if line.strip():
id, _, x, y, z = line.split(',')
point = arcpy.Point(float(x), float(y), float(z))
points.append(point)

if len(points) == 5:
if points[0] != points[-1]:
points.append(points[0]) # Ensure the polygon is closed
polygon = arcpy.Polygon(arcpy.Array(points), self.spatial_reference, True)
cursor.insertRow([polygon, group_id])
points = [] # Reset for next group
group_id += 1

del cursor

if __name__ == "__main__":
input_directory = r'C:\Tutorial\GIS\ArcPyTutorial\Data\MyTestFolder'
output_directory = r'C:\Tutorial\GIS\ArcPyTutorial\Data\MyTestFolder\outPut'
converter = TextToShapefileConverter(input_directory, output_directory)

# Process each file
for filename in os.listdir(input_directory):
if filename.endswith('.txt'😞
converter.convert(filename)

Re: cannot view the shapeFile generated from points

Clubdebambos — Thu, 08 Feb 2024 09:25:18 GMT

Looking at your Y values this is pretty much a straight line. You are probably breaking polygon rules with self intersections when you close the polygon.

Re: cannot view the shapeFile generated from points

mokamuralidhar — Thu, 08 Feb 2024 16:52:37 GMT

Thanks for looking into this. This is actually a trapezoid. If you use the method def _create_polyline_shapefile. It creates the line shape. The problem is actually when it is generated as a polygon shape, which is the other method "_create_polygon_shapefile". When we try to generate as a shape, it does not show the graphics.

Re: cannot view the shapeFile generated from points

KimOllivier — Sun, 11 Feb 2024 11:22:56 GMT

There is no need to create a new class. Just a function would do. Shapefiles are obsolete with lots of limitations, use a featureclass in a filegeodatabase. Then you can have null geometry for example.

There are much easier ways of loading data that this painful way that is also very old.

Here are 5 records of the in the PointFile
======================
id, shapeId, x, y, z
1,1,2197490.3821680555,1.5003079009938888E7,1573.2872741540364
2,2,2197478.7284111492,1.5003076194199622E7,1570.29
3,3,2197459.2878189506,1.500307149703293E7,1570.29
4,4,2197446.2932236306,1.5003068357325058E7,1573.6321294959107
5,5,2197490.3821680555,1.5003079009938888E7,1573.2872741540364

Here is the python program
===================
import arcpy
import os

class TextToShapefileConverter:
def __init__(self, input_directory, output_directory, spatial_reference_id=26914😞
self.input_directory = input_directory
self.output_directory = output_directory
self.spatial_reference_id = spatial_reference_id
self.spatial_reference = arcpy.SpatialReference(self.spatial_reference_id)

def convert(self, point_file_name):
input_text_file = os.path.join(self.input_directory, point_file_name)
output_shapefile_name = os.path.splitext(point_file_name)[0] + '.shp'
output_shapefile = os.path.join(self.output_directory, output_shapefile_name)

print "generating", output_shapefile_name

if "PolygonPointFile" in point_file_name:
self._create_polyline_shapefile(output_shapefile, input_text_file)
# self._create_polygon_shapefile(output_shapefile, input_text_file)

def _create_polyline_shapefile(self, output_shapefile, input_text_file):
arcpy.env.overwriteOutput = True
arcpy.CreateFeatureclass_management(
os.path.dirname(output_shapefile),
os.path.basename(output_shapefile),
"POLYLINE", has_z="ENABLED", has_m="DISABLED",
spatial_reference=self.spatial_reference)
arcpy.AddField_management(output_shapefile, "PairID", "LONG")

cursor = arcpy.da.InsertCursor(output_shapefile, ['SHAPE@', 'PairID'])
points = []
pair_id = 0

with open(input_text_file, 'r') as file:
next(file) # Skip header
for line in file:
if line.strip():
_, _, x, y, z = line.split(',')
point = arcpy.Point(float(x), float(y), float(z))
points.append(point)

# Check if a pair of points has been added
if len(points) == 5:
print points
polyline = arcpy.Polyline(arcpy.Array(points), self.spatial_reference, True)
cursor.insertRow([polyline, pair_id])
points = [] # Reset for next pair
pair_id += 1

del cursor

def _create_polygon_shapefile(self, output_shapefile, input_text_file):
arcpy.env.overwriteOutput = True
arcpy.CreateFeatureclass_management(
os.path.dirname(output_shapefile),
os.path.basename(output_shapefile),
"POLYGON", has_z="ENABLED", has_m="DISABLED",
spatial_reference=self.spatial_reference)
arcpy.AddField_management(output_shapefile, "GroupID", "LONG")

cursor = arcpy.da.InsertCursor(output_shapefile, ['SHAPE@', 'GroupID'])
points = []
group_id = 0

with open(input_text_file, 'r') as file:
next(file) # Skip header
for line in file:
if line.strip():
id, _, x, y, z = line.split(',')
point = arcpy.Point(float(x), float(y), float(z))
points.append(point)

if len(points) == 5:
if points[0] != points[-1]:
points.append(points[0]) # Ensure the polygon is closed
polygon = arcpy.Polygon(arcpy.Array(points), self.spatial_reference, True)
cursor.insertRow([polygon, group_id])
points = [] # Reset for next group
group_id += 1

del cursor

if __name__ == "__main__":
input_directory = r'C:\Tutorial\GIS\ArcPyTutorial\Data\MyTestFolder'
output_directory = r'C:\Tutorial\GIS\ArcPyTutorial\Data\MyTestFolder\outPut'
converter = TextToShapefileConverter(input_directory, output_directory)

# Process each file
for filename in os.listdir(input_directory):
if filename.endswith('.txt'😞
converter.convert(filename)