Im Folgenden finden Sie eine Möglichkeit, mit Python auf Breiten- und Längenkoordinaten von ESRI-Shapefiles zuzugreifen, unter anderem auf Informationen wie Raumbezug, Feldattribute, Feldwerte usw. Der folgende Code funktioniert nur für Polygone und Punkte (weil ich nicht dazu gekommen bin, den Code für Polylinien zu schreiben). Ich habe im Grunde genommen einen Code zusammengeschustert, den ich in der ArcGIS Desktop-Hilfe 9.3 verstreut gefunden habe, einen eigenen hinzugefügt und ihn in einer Funktion zusammengefasst. Es wurde mit ArcGIS 9.3 geschrieben. Sie sollten in der Lage sein, ein Polygon-Shapefile oder ein Punkt-Shapefile zu übergeben, und die Logik leitet es entsprechend.
def get_shapefile( shape_file ):
# Import native arcgisscripting module
import arcgisscripting
# Create the geoprocessor object
gp = arcgisscripting.create(9.3)
# Identify the geometry field
desc = gp.Describe( shape_file )
shapefieldname = desc.ShapeFieldName
# Get shapefile Name
print
print 'Shapefile Name: ', desc.Name
# Get the spatial reference
spatial_reference = desc.SpatialReference.Name
print 'Spatial Reference: ', spatial_reference
print
# Create search cursor
rows = gp.SearchCursor( shape_file )
row = rows.Next()
# Enter while loop for each feature/row
while row:
# Create the geometry object
feat = row.GetValue(shapefieldname)
print '*' * 30
print
print 'Geometry related Information'
print
# Get Geometry Type
geometry_Type = feat.Type
print 'Geometry Type: ', geometry_Type
# Get the area of the feature
geometry_Area = feat.Area
print 'geometry_Area; ', geometry_Area
# Get the centroid for the feature
geometry_Centroid = feat.Centroid
print 'geometry_Centroid:', geometry_Centroid
# Get the extent for the feature
geometry_Extent = feat.Extent
print 'geometry_extent: ', geometry_Extent
print
print 'Get Attribute Table Information'
# Get all the fields for the feature class
fields = desc.Fields
total_number_of_fields = len( fields )
print 'Total number of fields: ', total_number_of_fields
print
print 'List attribute table related information:'
print
field_num_cntr = 0
# Loop through all the fields in the feature class
for field in fields:
print '*'*5, field_num_cntr, '*'*5
print
print 'field Type: ', field.Type
print 'Scale: ', str(field.Scale)
print 'Precision: ', str(field.Precision)
print field.Name, '=> ', row.GetValue( field.Name )
print
field_num_cntr += 1
if geometry_Type == 'polygon':
# Variable to keep track of how many multipart polygons are in
# featureclass
partnum = 0
# Count the number of points in the current multipart feature
partcount = feat.PartCount
print
print 'Number of polygons in feature class: ', partcount
print
# Enter while loop for each part in the feature (if a singlepart feature
# this will occur only once)
while partnum < partcount:
# Print the part number
print "Part ", str(partnum), "of", partcount, ":"
print
part = feat.GetPart(partnum)
pnt = part.Next()
pntcount = 0
# Enter while loop for each vertex
while pnt:
# Print x,y coordinates of current point
print 'X coord:', pnt.x, 'Y coord:', pnt.y
pnt = part.Next()
pntcount += 1
# If pnt is null, either the part is finished or there is an interior ring
if not pnt:
pnt = part.Next()
if pnt:
print "Interior Ring:"
partnum += 1
print
print 'Number of coordinates in feature class: ', pntcount - 1
print
elif geometry_Type == 'point':
feat = row.GetValue(shapefieldname)
# Get coords
pnt = feat.GetPart()
# Print x,y coordinates of current point object
print 'X coord:', pnt.x, 'Y coord:', pnt.y
row = rows.Next()
your_shapefile = 'Path\To\Your\Shapefile.shp'
get_shapefile( your_shapefile )