SpatialReference

Resumen

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

Debate

A SpatialReference can be easily created from existing datasets and PRJ files:

  1. Use a PRJ file as an argument to the SpatialReference class.
    import arcpy, os
prjFile = os.path.join(arcpy.GetInstallInfo()["InstallDir"],
                       "Coordinate Systems/Geographic Coordinate Systems/North America/NAD 1983.prj")
spatialRef = arcpy.SpatialReference(prjFile)
  2. Describe a dataset and access its spatialReference property.
    dataset = "C:/Data/Landbase.gdb/Wetlands"
spatialRef = arcpy.Describe(dataset).spatialReference
NotaNota:

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.

Sintaxis

SpatialReference (prjFile)
ParámetroExplicaciónTipo de datos
prjFile

The projection file used to populate the spatial reference object.

String

Propiedades

PropiedadExplicaciónTipo de datos
MDomain
(Sólo lectura)

The extent of the measure domain.

String
MFalseOriginAndUnits
(Sólo lectura)

The measure false origin and units.

String
MResolution
(Lectura y escritura)

The measure resolution.

Double
MTolerance
(Lectura y escritura)

The measure tolerance.

Double
XYResolution
(Lectura y escritura)

The xy resolution.

Double
XYTolerance
(Lectura y escritura)

The xy tolerance.

Double
ZDomain
(Sólo lectura)

The extent of the Z domain.

String
ZFalseOriginAndUnits
(Sólo lectura)

The Z false origin and units.

String
ZResolution
(Lectura y escritura)

The Z resolution property.

Double
ZTolerance
(Lectura y escritura)

The Z tolerance property.

Double
abbreviation
(Lectura y escritura)

The abbreviated name of the spatial reference.

String
alias
(Lectura y escritura)

The alias of the spatial reference.

String
domain
(Sólo lectura)

The extent of the xy domain.

String
factoryCode
(Lectura y escritura)

The factory code of the spatial reference.

Integer
falseOriginAndUnits
(Sólo lectura)

The false origin and units.

String
hasMPrecision
(Sólo lectura)

Indicates whether or not m-value precision information has been defined.

Boolean
hasXYPrecision
(Sólo lectura)

Indicates whether or not xy precision information has been defined.

Boolean
hasZPrecision
(Sólo lectura)

Indicates whether or not z-value precision information has been defined.

Boolean
isHighPrecision
(Lectura y escritura)

Indicates whether or not the spatial reference has high precision set.

Boolean
name
(Lectura y escritura)

The name of the spatial reference.

String
remarks
(Lectura y escritura)

The comment string of the spatial reference.

String
type
(Lectura y escritura)

The type of the spatial reference.

String
usage
(Sólo lectura)

The usage notes.

String
PCSCode
(Lectura y escritura)

The projected coordinate system code.1

Integer
PCSName
(Lectura y escritura)

The projected coordinate system name.1

String
azimuth
(Lectura y escritura)

The azimuth of a projected coordinate system.1

Double
centralMeridian
(Lectura y escritura)

The central meridian of a projected coordinate system.1

Double
centralMeridianInDegrees
(Lectura y escritura)

The central meridian (Lambda0) of a projected coordinate system in degrees.1

Double
centralParallel
(Lectura y escritura)

The central parallel of a projected coordinate system.1

Double
classification
(Sólo lectura)

The classification of a map projection.1

String
falseEasting
(Lectura y escritura)

The false easting of a projected coordinate system.1

Double
falseNorthing
(Lectura y escritura)

The false northing of a projected coordinate system.1

Double
latitudeOf1st
(Lectura y escritura)

The latitude of the first point of a projected coordinate system.1

Double
latitudeOf2nd
(Lectura y escritura)

The latitude of the second point of a projected coordinate system.1

Double
linearUnitCode
(Lectura y escritura)

The linear unit code.1

Integer
linearUnitName
(Lectura y escritura)

The linear unit name.1

String
longitude
(Lectura y escritura)

The longitude value of this prime meridian.1

Double
longitudeOf1st
(Lectura y escritura)

The longitude of the first point of a projected coordinate system.1

Double
longitudeOf2nd
(Lectura y escritura)

The longitude of the second point of a projected coordinate system.1

Double
longitudeOfOrigin
(Lectura y escritura)

The longitude of origin of a projected coordinate system.1

Double
projectionCode
(Lectura y escritura)

The projection code.1

Integer
projectionName
(Lectura y escritura)

The projection name.1

String
scaleFactor
(Lectura y escritura)

The scale factor of a projected coordinate system.1

Double
standardParallel1
(Lectura y escritura)

The first parallel of a projected coordinate system.1

Double
standardParallel2
(Lectura y escritura)

The second parallel of a projected coordinate system.1

Double
GCSCode
(Lectura y escritura)

The geographic coordinate system code.2

Integer
GCSName
(Lectura y escritura)

The geographic coordinate system name.2

String
angularUnitCode
(Lectura y escritura)

The angular unit code.2

Integer
angularUnitName
(Lectura y escritura)

The angular unit name.2

String
datumCode
(Lectura y escritura)

The datum code.2

Integer
datumName
(Lectura y escritura)

The datum name.2

String
flattening
(Lectura y escritura)

The flattening ratio of this spheroid.2

Double
longitude
(Lectura y escritura)

The longitude value of this prime meridian.2

Double
primeMeridianCode
(Lectura y escritura)

The prime meridian code.2

Integer
primeMeridianName
(Lectura y escritura)

The prime meridian name.2

String
radiansPerUnit
(Sólo lectura)

The radians per angular unit.2

Double
semiMajorAxis
(Lectura y escritura)

The semi-major axis length of this spheroid.2

Double
semiMinorAxis
(Lectura y escritura)

The semi-minor axis length of this spheroid.2

Double
spheroidCode
(Lectura y escritura)

The spheroid code.2

Integer
spheroidName
(Lectura y escritura)

The spheroid name.2

String

Vista general del método

MétodoExplicación
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.

setZDomain (z_min, z_max)

Sets the Z domain.

setMFalseOriginAndUnits (false_m, m_units)

Sets the M false origin and units.

setZFalseOriginAndUnits (false_z, z_units)

Sets the Z false origin and units.

Métodos

create ()
createFromFile (prj_file)
ParámetroExplicaciónTipo de datos
prj_file

The projection file used to populate the spatial reference object.

String
exportToString ()
Valor de retorno
Tipo de datosExplicación
String

The string representation of the object.

loadFromString (string)
ParámetroExplicaciónTipo de datos
string

The string representation of the object.

String
setDomain (x_min, x_max, y_min, y_max)
ParámetroExplicaciónTipo de datos
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)
ParámetroExplicaciónTipo de datos
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)
ParámetroExplicaciónTipo de datos
m_min

The minimum m-value.

Double
m_max

The maximum m-value.

Double
setZDomain (z_min, z_max)
ParámetroExplicaciónTipo de datos
z_min

The minimum z-value.

Double
z_max

The maximum z-value.

Double
setMFalseOriginAndUnits (false_m, m_units)
ParámetroExplicaciónTipo de datos
false_m

The false m-value.

Double
m_units

The m units.

Double
setZFalseOriginAndUnits (false_z, z_units)
ParámetroExplicaciónTipo de datos
false_z

The false z-value.

Double
z_units

The false z units.

Double

Ejemplo de código

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 example 2

Create a SpatialReference using a .prj file.

import arcpy

prjFile = "c:/Program Files/ArcGIS/Desktop10.0/Coordinate Systems/Projected Coordinate Systems" + \
           "/Continental/North America/USA Contiguous Equidistant Conic.prj"

# Create a spatial reference object using a projection file
#
sr = arcpy.SpatialReference(prjFile)
SpatialReference example 3

Create a SpatialReference from a factory code.

import arcpy

# Create a spatial reference object using a factory code
#
sr = arcpy.SpatialReference()
sr.factoryCode = 3857
sr.create()

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7/10/2012