ArcGIS Help 10.1 - SpatialReference (arcpy)

Zusammenfassung

Each part of the spatial reference has a number of properties (especially the coordinate system) that defines what map projection options are used to define horizontal coordinates.

Diskussion

A SpatialReference object can also be accessed from existing datasets using the Describe spatialReference property.

dataset = "C:/Data/Landbase.gdb/Wetlands"
spatialRef = arcpy.Describe(dataset).spatialReference

Hinweis:

Which spatial reference properties are available depends on the coordinate system used. In the properties list below, those properties only available with a Projected Coordinate system are denoted with a ¹; properties available only with a Geographic Coordinate system are denoted with a ².

Syntax

SpatialReference ({item})

Parameter Erläuterung Datentyp

item

The spatial reference can be created in three ways:

Using the name of the coordinate system

sr = arcpy.SpatialReference("Hawaii Albers Equal Area Conic")

Using a projection file (.prj)

sr = arcpy.SpatialReference("c:/coordsystems/NAD 1983.prj")

Using a coordinate system's factory code (or authority code)

# 32145 is the code for: 
#  NAD 1983 StatePlane Vermont FIPS 4400 (Meters)
sr = arcpy.SpatialReference(32145)

For more information on coordinate system names and factory codes, see geographic_coordinate_systems.pdf and projected_coordinate_systems.pdf files in the ArcGIS Documentation folder.

For more information, see Using the spatial reference class.

String

Eigenschaften

Eigenschaft	Erläuterung	Datentyp
GCS (Schreibgeschützt)	If a projected coordinate system, returns a SpatialReference object for the geographic coordinate system it is based on. If a geographic coordinate system, returns the same SpatialReference.	SpatialReference
MDomain (Schreibgeschützt)	The extent of the measure domain.	String
MFalseOriginAndUnits (Schreibgeschützt)	The measure false origin and units.	String
MResolution (Lesen und schreiben)	The measure resolution.	Double
MTolerance (Lesen und schreiben)	The measure tolerance.	Double
XYResolution (Lesen und schreiben)	The xy resolution.	Double
XYTolerance (Lesen und schreiben)	The xy tolerance.	Double
ZDomain (Schreibgeschützt)	The extent of the Z domain.	String
ZFalseOriginAndUnits (Schreibgeschützt)	The Z false origin and units.	String
ZResolution (Lesen und schreiben)	The Z resolution property.	Double
ZTolerance (Lesen und schreiben)	The Z tolerance property.	Double
abbreviation (Lesen und schreiben)	The abbreviated name of the spatial reference.	String
alias (Lesen und schreiben)	The alias of the spatial reference.	String
domain (Schreibgeschützt)	The extent of the xy domain.	String
factoryCode (Lesen und schreiben)	The factory code of the spatial reference.	Integer
falseOriginAndUnits (Schreibgeschützt)	The false origin and units.	String
hasMPrecision (Schreibgeschützt)	Indicates whether or not m-value precision information has been defined.	Boolean
hasXYPrecision (Schreibgeschützt)	Indicates whether or not xy precision information has been defined.	Boolean
hasZPrecision (Schreibgeschützt)	Indicates whether or not z-value precision information has been defined.	Boolean
isHighPrecision (Lesen und schreiben)	Indicates whether or not the spatial reference has high precision set.	Boolean
name (Lesen und schreiben)	The name of the spatial reference.	String
remarks (Lesen und schreiben)	The comment string of the spatial reference.	String
type (Lesen und schreiben)	The type of the spatial reference.	String
usage (Schreibgeschützt)	The usage notes.	String
PCSCode (Lesen und schreiben)	The projected coordinate system code.¹	Integer
PCSName (Lesen und schreiben)	The projected coordinate system name.¹	String
azimuth (Lesen und schreiben)	The azimuth of a projected coordinate system.¹	Double
centralMeridian (Lesen und schreiben)	The central meridian of a projected coordinate system.¹	Double
centralMeridianInDegrees (Lesen und schreiben)	The central meridian (Lambda0) of a projected coordinate system in degrees.¹	Double
centralParallel (Lesen und schreiben)	The central parallel of a projected coordinate system.¹	Double
classification (Schreibgeschützt)	The classification of a map projection.¹	String
falseEasting (Lesen und schreiben)	The false easting of a projected coordinate system.¹	Double
falseNorthing (Lesen und schreiben)	The false northing of a projected coordinate system.¹	Double
latitudeOf1st (Lesen und schreiben)	The latitude of the first point of a projected coordinate system.¹	Double
latitudeOf2nd (Lesen und schreiben)	The latitude of the second point of a projected coordinate system.¹	Double
linearUnitCode (Lesen und schreiben)	The linear unit code.¹	Integer
linearUnitName (Lesen und schreiben)	The linear unit name.¹	String
longitude (Lesen und schreiben)	The longitude value of this prime meridian.¹	Double
longitudeOf1st (Lesen und schreiben)	The longitude of the first point of a projected coordinate system.¹	Double
longitudeOf2nd (Lesen und schreiben)	The longitude of the second point of a projected coordinate system.¹	Double
longitudeOfOrigin (Lesen und schreiben)	The longitude of origin of a projected coordinate system.¹	Double
projectionCode (Lesen und schreiben)	The projection code.¹	Integer
projectionName (Lesen und schreiben)	The projection name.¹	String
scaleFactor (Lesen und schreiben)	The scale factor of a projected coordinate system.¹	Double
standardParallel1 (Lesen und schreiben)	The first parallel of a projected coordinate system.¹	Double
standardParallel2 (Lesen und schreiben)	The second parallel of a projected coordinate system.¹	Double
GCSCode (Lesen und schreiben)	Der Code des geographischen Koordinatensystems.²	Integer
GCSName (Lesen und schreiben)	Der Name des geographischen Koordinatensystems.²	String
angularUnitCode (Lesen und schreiben)	Der Code der Winkeleinheit.²	Integer
angularUnitName (Lesen und schreiben)	Der Name der Winkeleinheit.²	String
datumCode (Lesen und schreiben)	Der Code des Datums.²	Integer
datumName (Lesen und schreiben)	Der Name des Datums.²	String
Abplattung (Lesen und schreiben)	Das Abflachungsverhältnis dieses Sphäroids.²	Double
Längengrad (Lesen und schreiben)	Der Längengradwert für diesen Nullmeridian.²	Double
primeMeridianCode (Lesen und schreiben)	Der Code des Nullmeridians.²	Integer
primeMeridianName (Lesen und schreiben)	Der Name des Nullmeridians.²	String
radiansPerUnit (Schreibgeschützt)	Radianten pro Winkeleinheit.²	Double
semiMajorAxis (Lesen und schreiben)	Die Länge der großen Hauptachse dieses Sphäroids.²	Double
semiMinorAxis (Lesen und schreiben)	Die Länge der kleinen Hauptachse dieses Sphäroids.²	Double
spheroidCode (Lesen und schreiben)	Der Code des Sphäroids.²	Integer
spheroidName (Lesen und schreiben)	Der Name des Sphäroids.²	String

Methodenübersicht

Methode	Erläuterung
create ()	Creates the spatial reference object using properties.
createFromFile (prj_file)	Creates the spatial reference object from a projection file.
exportToString ()	Exports the object to its string representation.
loadFromString (string)	Restore the object using its string representation. The exportToString method can be used to create a string representation.
setDomain (x_min, x_max, y_min, y_max)	Sets the XY domain.
setFalseOriginAndUnits (false_x, false_y, xy_units)	Sets the XY false origin and units.
setMDomain (m_min, m_max)	Sets the M domain.
setMFalseOriginAndUnits (false_m, m_units)	Sets the M false origin and units.
setZDomain (z_min, z_max)	Sets the Z domain.
setZFalseOriginAndUnits (false_z, z_units)	Sets the Z false origin and units.

Methoden

create ()

createFromFile (prj_file)

Parameter	Erläuterung	Datentyp
prj_file	The projection file used to populate the spatial reference object.	String

exportToString ()

Rückgabewert

Datentyp	Erläuterung
String	The string representation of the object.

loadFromString (string)

Parameter	Erläuterung	Datentyp
string	The string representation of the object.	String

setDomain (x_min, x_max, y_min, y_max)

Parameter	Erläuterung	Datentyp
x_min	The minimum x-value.	Double
x_max	The maximum x-value.	Double
y_min	The minimum y-value.	Double
y_max	The maximum y-value.	Double

setFalseOriginAndUnits (false_x, false_y, xy_units)

Parameter	Erläuterung	Datentyp
false_x	The false x value.	Double
false_y	The false y value.	Double
xy_units	The xy units.	String

setMDomain (m_min, m_max)

Parameter	Erläuterung	Datentyp
m_min	The minimum m-value.	Double
m_max	The maximum m-value.	Double

setMFalseOriginAndUnits (false_m, m_units)

Parameter	Erläuterung	Datentyp
false_m	The false m-value.	Double
m_units	The m units.	Double

setZDomain (z_min, z_max)

Parameter	Erläuterung	Datentyp
z_min	The minimum z-value.	Double
z_max	The maximum z-value.	Double

setZFalseOriginAndUnits (false_z, z_units)

Parameter	Erläuterung	Datentyp
false_z	The false z-value.	Double
z_units	The false z units.	Double

Codebeispiel

SpatialReference example

For each feature class in a workspace, print the name of its spatial reference.

import arcpy
from arcpy import env

# Set the workspace environment
#
env.workspace = "C:/base/base.gdb"

# Get a list of the feature classes in the input folder
#
fcs = arcpy.ListFeatureClasses()

# Loop through the list
#
for fc in fcs:
    # Create the spatial reference object
    #
    sr = arcpy.Describe(fc).spatialReference

    # If the spatial reference is unknown
    #
    if sr.name == "Unknown":
        print fc + " has an unknown spatial reference\n"

    # Otherwise, print out the feature class name and
    #   spatial reference
    #
    else:
        print fc + ": " + sr.name + "\n"

SpatialReference (arcpy)