Skip to main content

SpatialReference

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"
spatial_ref = arcpy.Describe(dataset).spatialReference

XY, Z, and M extents are not the same as spatial reference domains. The XY, Z, and M domains in a spatial reference define the valid range of coordinate values that can be stored in a feature class. The feature class extents reflect the actual range of coordinate values that exist in the feature class. These extents cannot be larger than the domains.

The SpatialReference object supports equal (==) and not equal (!=) operators for comparing spatial references.

Hinweis:

The spatial reference properties available depend on the coordinate system used. In the properties list below, those properties that are only available with a projected coordinate system are denoted with a 1; properties only available with a geographic coordinate system are denoted with a 2.

Because a projected coordinate system is based on a geographic coordinate system, projected coordinate system properties can be accessed from a geographic coordinate system using the GCS property.

Syntax

SpatialReference({item}, {vcs}, {text})

Name Erläuterung Datentyp

item

(Optional)

The horizontal coordinate system used to create the SpatialReference object. The coordinate system can be set using a projection file, name, or factory code.

Create a SpatialReference object using the display name of a coordinate system.

sr = arcpy.SpatialReference("Sinusoidal (world)")

Create a SpatialReference object using the canonical name of a coordinate system.

sr = arcpy.SpatialReference("World_Sinusoidal")

Create a SpatialReference object using a coordinate system's factory code (or authority code or WKID).

# The factory code of 32145 represents:
# NAD 1983 StatePlane Vermont FIPS 4400 (Meters)

sr = arcpy.SpatialReference(32145)

Create a SpatialReference object using a projection file (.prj).

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

For more information about coordinate system names and factory codes, see the geographic_coordinate_systems.pdf and projected_coordinate_systems.pdf files.

For more information, see Using the spatial reference class.

Variant

vcs

(Optional)

The vertical coordinate system (VCS). The VCS defines information about the z-coordinates and can be set using a name or factory code. See the following examples:

Define the vertical coordinate system using a name.

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

Define the vertical coordinate system using a factory code.

# Spatial Reference factory code of 32145 is : NAD 1983 StatePlane Vermont FIPS 4400 (Meters)
# Spatial Reference factory code of 5714 is : Mean Sea Level (Height)

sr = arcpy.SpatialReference(32145, 5714)

Variant

text

(Optional)

A well-known text (WKT or WKT2 format) string that can be used to define a horizontal and vertical coordinate system.

Hinweis:

When creating a SpatialReference object with a vertical coordinate system using the text argument, define the vertical coordinate system using the VERTCS section of the WKT string. The vcs argument is not used.

Create a SpatialReference object using a WKT string with a horizontal coordinate system.

# String below is the WKT for the
# Geographic Coordinate system "WGS 1984" (factory code=4326)
wkt = """
GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984',SPHEROID['WGS_1984',6378137.0,298.257223563]],
PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]];
-400 -400 1000000000;-100000 10000;-100000 10000;8.98315284119522E-09;
0.001;0.001;IsHighPrecision
"""

sr = arcpy.SpatialReference(text=wkt)

Create a SpatialReference object using a WKT2 string with a horizontal coordinate system.

# The following string is the WKT2 for the
# Projected Coordinate System "NAD 1983 StatePlane California V FIPS 0405 (US FEET)
# (factory code=2229)
wkt2 = """
PROJCRS[
   "NAD_1983_StatePlane_California_V_FIPS_0405_Feet",
   BASEGEOGCRS["GCS_North_American_1983",DATUM["D_North_American_1983",
   ELLIPSOID["GRS_1980",6378137.0,298.257222101,LENGTHUNIT["Meter",1.0]]
],
PRIMEM["Greenwich",0.0,ANGLEUNIT["Degree",0.017453292519943295]],CS[ellipsoidal,2],
AXIS["Latitude (lat)",north,ORDER[1]],AXIS["Longitude (lon)",east,ORDER[2]],
ANGLEUNIT["Degree",0.017453292519943295]],
CONVERSION["Lambert_Conformal_Conic",METHOD["Lambert_Conformal_Conic"],
PARAMETER["False_Easting",6561666.666666666,LENGTHUNIT["Foot_US",0.30480060960121924]],
PARAMETER["False_Northing",1640416.666666667,LENGTHUNIT["Foot_US",0.30480060960121924]],
PARAMETER["Central_Meridian",-118.0,ANGLEUNIT["Degree",0.017453292519943295]],
PARAMETER["Standard_Parallel_1",34.033333333333331,ANGLEUNIT["Degree",0.017453292519943295]],
PARAMETER["Standard_Parallel_2",35.466666666666669,ANGLEUNIT["Degree",0.017453292519943295]],
PARAMETER["Latitude_Of_Origin",33.5,ANGLEUNIT["Degree",0.017453292519943295]]],CS[Cartesian,2],
AXIS["Easting (X)",east,ORDER[1]],AXIS["Northing (Y)",north,ORDER[2]],
LENGTHUNIT["Foot_US",0.30480060960121924]]
"""

sr = arcpy.SpatialReference(text=wkt2)

Create a SpatialReference object using a WKT string with a horizontal and vertical coordinate system.

# The following string is the WKT for the
# Geographic Coordinate system "WGS 1984" (factory code=4326)
wkt = """
GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984',SPHEROID['WGS_1984',6378137.0,298.257223563]],
PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]],
VERTCS['WGS_1984',DATUM['D_WGS_1984',SPHEROID['WGS_1984',6378137.0,298.257223563]],
PARAMETER['Vertical_Shift',0.0],PARAMETER['Direction',1.0],UNIT['Meter',1.0]];
-400 -400 1000000000;-100000 10000;-100000 10000;8.98315284119522E-09;
0.001;0.001;IsHighPrecision
"""

sr = arcpy.SpatialReference(text=wkt)

String

Eigenschaften

Name Erläuterung Datentyp

GCS

(Schreibgeschützt)

A projected coordinate system returns a SpatialReference object for the geographic coordinate system it is based on. A geographic coordinate system returns the same SpatialReference value.

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

VCS

(Schreibgeschützt)

If the coordinate system has a vertical coordinate system, the property returns a VCS object for the vertical coordinate system it is based on.

Object

XYResolution

(Lesen und schreiben)

The x,y-resolution.

Double

XYTolerance

(Lesen und schreiben)

The x,y-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.

Double

ZTolerance

(Lesen und schreiben)

The z-tolerance.

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 x,y-domain.

String

factoryCode

(Lesen und schreiben)

The factory code or well-known ID (WKID) of the spatial reference.

Integer

falseOriginAndUnits

(Schreibgeschützt)

The false origin and units.

String

hasMPrecision

(Schreibgeschützt)

Specifies whether m-value precision information has been defined.

Boolean

hasXYPrecision

(Schreibgeschützt)

Specifies whether x,y-coordinate precision information has been defined.

Boolean

hasZPrecision

(Schreibgeschützt)

Specifies whether z-value precision information has been defined.

Boolean

isHighPrecision

(Lesen und schreiben)

Specifies whether 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)

Specifies the type of the spatial reference.

  • Geographic—A geographic coordinate system

  • Projected—A projected coordinate system

  • Unknown—An unknown coordinate system

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

latitudeOfOrigin

(Lesen und schreiben)

The latitude of origin 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

metersPerUnit

(Schreibgeschützt)

The meters per linear unit.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)

The geographic coordinate system code.2

Integer

GCSName

(Lesen und schreiben)

The geographic coordinate system name.2

String

angularUnitCode

(Lesen und schreiben)

The angular unit code.2

Integer

angularUnitName

(Lesen und schreiben)

The angular unit name.2

String

datumCode

(Lesen und schreiben)

The datum code.2

Integer

datumName

(Lesen und schreiben)

The datum name.2

String

flattening

(Lesen und schreiben)

The flattening ratio of this spheroid.2

Double

longitude

(Lesen und schreiben)

The longitude value of this prime meridian.2

Double

primeMeridianCode

(Lesen und schreiben)

The prime meridian code.2

Integer

primeMeridianName

(Lesen und schreiben)

The prime meridian name.2

String

radiansPerUnit

(Schreibgeschützt)

The radians per angular unit.2

Double

semiMajorAxis

(Lesen und schreiben)

The semi-major axis length of this spheroid.2

Double

semiMinorAxis

(Lesen und schreiben)

The semi-minor axis length of this spheroid.2

Double

spheroidCode

(Lesen und schreiben)

The spheroid code.2

Integer

spheroidName

(Lesen und schreiben)

The spheroid name.2

String

Methoden

create()

Creates the SpatialReference object using properties.

createFromFile(prj_file)

Creates the SpatialReference object from a projection file.

Name Erläuterung Datentyp

prj_file

The projection file used to populate the SpatialReference object.

String

exportToString({encoding})

Exports the object to its string representation.

Name Erläuterung Datentyp

encoding

(Optional)

Specifies the encoding of the exported string.

  • WKT—The spatial reference will be exported to the WKT standard.

  • WKT2—The spatial reference will be exported to the WKT 2 standard.

The default value is WKT.

String

Rückgabewert

Datentyp Erläuterung

String

The WKT or WKT 2 representation of the object.

loadFromString(string)

Defines a SpatialReference object from a WKT string.

The exportToString method can be used to export a WKT string representation of the spatial reference.

  • Using a WKT string with a horizontal coordinate system.

    # The following string is the WKT for the
# Geographic Coordinate system "WGS 1984" (factory code=4326)
wkt = 'GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],\
              PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]];\
              -400 -400 1000000000;-100000 10000;-100000 10000;8.98315284119522E-09;\
              0.001;0.001;IsHighPrecision'

sr = arcpy.SpatialReference()
sr.loadFromString(wkt)

  • Using a WKT string with a horizontal and vertical coordinate system. Note that the vertical coordinate system is defined in the VERTCS section of the WKT.

    # The following string is the WKT for the
# Geographic Coordinate system "WGS 1984" (factory code=4326),
# with a vertical coordinate system "WGS 1984" (factory code=115700)
wkt = 'GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],\
              PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],\
              VERTCS["WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],\
              PARAMETER["Vertical_Shift",0.0],PARAMETER["Direction",1.0],UNIT["Meter",1.0]];\
              -400 -400 1000000000;-100000 10000;-100000 10000;8.98315284119522E-09;\
              0.001;0.001;IsHighPrecision'

sr = arcpy.SpatialReference()
sr.loadFromString(wkt)
Name Erläuterung Datentyp

string

The WKT string representation of the object.

String

setDomain(x_min, x_max, y_min, y_max)

Sets the x,y-domain.

Name 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)

Sets the false x,y origin and units.

Name Erläuterung Datentyp

false_x

The false x-value.

Double

false_y

The false y-value.

Double

xy_units

The x,y-units.

String

setMDomain(m_min, m_max)

Sets the m-domain.

Name Erläuterung Datentyp

m_min

The minimum m-value.

Double

m_max

The maximum m-value.

Double

setMFalseOriginAndUnits(false_m, m_units)

Sets the false m origin and units.

Name Erläuterung Datentyp

false_m

The false m-value.

Double

m_units

The m-units.

Double

setZDomain(z_min, z_max)

Sets the z-domain.

Name Erläuterung Datentyp

z_min

The minimum z-value.

Double

z_max

The maximum z-value.

Double

setZFalseOriginAndUnits(false_z, z_units)

Sets the false z origin and units.

Name 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

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

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

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

    # If the spatial reference is unknown
    if spatial_ref.name == "Unknown":
        print(r"{fc} has an unknown spatial reference")

    # Otherwise, print out the feature class name and spatial reference
    else:
        print(f"{fc} : {spatial_ref.name}")