サマリー
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.
説明
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
構文
 SpatialReference  ({item}, {vcs})| パラメーター | 説明 | データ タイプ | 
item  | The coordinate system to be used to create the SpatialReference. Can be set using a projection file, name, factory code, or well-known text (WKT) format. See examples below. 
 For more information on coordinate system names and factory codes, see geographic_coordinate_systems.pdf and projected_coordinate_systems.pdf files. For more information, see Using the spatial reference class.  | Variant | 
vcs  | The vertical coordinate system (VCS). The VCS defines information about the Z coordinates. Can be set using a name, factory code, or well-known text (WKT) format. See examples below. 
  | Variant | 
プロパティ
| プロパティ | 説明 | データ タイプ | 
| GCS (読み取り専用)  | 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.  | SpatialReference | 
| MDomain (読み取り専用)  | The extent of the measure domain.  | String | 
| MFalseOriginAndUnits (読み取り専用)  | The measure false origin and units.  | String | 
| MResolution (読み書き)  | The measure resolution.  | Double | 
| MTolerance (読み書き)  | The measure tolerance.  | Double | 
| VCS (読み取り専用)  | If the coordinate system has a vertical coordinate system, it returns a VCS object for the vertical coordinate system it is based on.  | Object | 
| XYResolution (読み書き)  | The xy resolution.  | Double | 
| XYTolerance (読み書き)  | The xy tolerance.  | Double | 
| ZDomain (読み取り専用)  | The extent of the z domain.  | String | 
| ZFalseOriginAndUnits (読み取り専用)  | The z false origin and units.  | String | 
| ZResolution (読み書き)  | The z resolution property.  | Double | 
| ZTolerance (読み書き)  | The z-tolerance property.  | Double | 
| abbreviation (読み書き)  | The abbreviated name of the spatial reference.  | String | 
| alias (読み書き)  | The alias of the spatial reference.  | String | 
| domain (読み取り専用)  | The extent of the xy domain.  | String | 
| factoryCode (読み書き)  | The factory code or well-known ID (WKID) of the spatial reference.  | Integer | 
| falseOriginAndUnits (読み取り専用)  | The false origin and units.  | String | 
| hasMPrecision (読み取り専用)  | Indicates whether m-value precision information has been defined.  | Boolean | 
| hasXYPrecision (読み取り専用)  | Indicates whether xy precision information has been defined.  | Boolean | 
| hasZPrecision (読み取り専用)  | Indicates whether z-value precision information has been defined.  | Boolean | 
| isHighPrecision (読み書き)  | Indicates whether the spatial reference has high precision set.  | Boolean | 
| name (読み書き)  | The name of the spatial reference.  | String | 
| remarks (読み書き)  | The comment string of the spatial reference.  | String | 
| type (読み書き)  | The type of the spatial reference.  | String | 
| usage (読み取り専用)  | The usage notes.  | String | 
| PCSCode (読み書き)  | The projected coordinate system code.1  | Integer | 
| PCSName (読み書き)  | The projected coordinate system name.1  | String | 
| azimuth (読み書き)  | The azimuth of a projected coordinate system.1  | Double | 
| centralMeridian (読み書き)  | The central meridian of a projected coordinate system.1  | Double | 
| centralMeridianInDegrees (読み書き)  | The central meridian (Lambda0) of a projected coordinate system in degrees.1  | Double | 
| centralParallel (読み書き)  | The central parallel of a projected coordinate system.1  | Double | 
| classification (読み取り専用)  | The classification of a map projection.1  | String | 
| falseEasting (読み書き)  | The false easting of a projected coordinate system.1  | Double | 
| falseNorthing (読み書き)  | The false northing of a projected coordinate system.1  | Double | 
| latitudeOf1st (読み書き)  | The latitude of the first point of a projected coordinate system.1  | Double | 
| latitudeOf2nd (読み書き)  | The latitude of the second point of a projected coordinate system.1  | Double | 
| latitudeOfOrigin (読み書き)  | The latitude of origin of a projected coordinate system.1  | Double | 
| linearUnitCode (読み書き)  | The linear unit code.1  | Integer | 
| linearUnitName (読み書き)  | The linear unit name.1  | String | 
| longitude (読み書き)  | The longitude value of this prime meridian.1  | Double | 
| longitudeOf1st (読み書き)  | The longitude of the first point of a projected coordinate system.1  | Double | 
| longitudeOf2nd (読み書き)  | The longitude of the second point of a projected coordinate system.1  | Double | 
| longitudeOfOrigin (読み書き)  | The longitude of origin of a projected coordinate system.1  | Double | 
| metersPerUnit (読み取り専用)  | The meters per linear unit.1  | Double | 
| projectionCode (読み書き)  | The projection code.1  | Integer | 
| projectionName (読み書き)  | The projection name.1  | String | 
| scaleFactor (読み書き)  | The scale factor of a projected coordinate system.1  | Double | 
| standardParallel1 (読み書き)  | The first parallel of a projected coordinate system.1  | Double | 
| standardParallel2 (読み書き)  | The second parallel of a projected coordinate system.1  | Double | 
| GCSCode (読み書き)  | The geographic coordinate system code.2  | Integer | 
| GCSName (読み書き)  | The geographic coordinate system name.2  | String | 
| angularUnitCode (読み書き)  | The angular unit code.2  | Integer | 
| angularUnitName (読み書き)  | The angular unit name.2  | String | 
| datumCode (読み書き)  | The datum code.2  | Integer | 
| datumName (読み書き)  | The datum name.2  | String | 
| flattening (読み書き)  | The flattening ratio of this spheroid.2  | Double | 
| longitude (読み書き)  | The longitude value of this prime meridian.2  | Double | 
| primeMeridianCode (読み書き)  | The prime meridian code.2  | Integer | 
| primeMeridianName (読み書き)  | The prime meridian name.2  | String | 
| radiansPerUnit (読み取り専用)  | The radians per angular unit.2  | Double | 
| semiMajorAxis (読み書き)  | The semi-major axis length of this spheroid.2  | Double | 
| semiMinorAxis (読み書き)  | The semi-minor axis length of this spheroid.2  | Double | 
| spheroidCode (読み書き)  | The spheroid code.2  | Integer | 
| spheroidName (読み書き)  | The spheroid name.2  | String | 
メソッドの概要
| メソッド | 説明 | 
| 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.  | 
メソッド
create ()
createFromFile (prj_file)
| パラメーター | 説明 | データ タイプ | 
prj_file  | The projection file used to populate the spatial reference object.  | String | 
exportToString ()
戻り値
| データ タイプ | 説明 | 
| String | The string representation of the object.  | 
loadFromString (string)
| パラメーター | 説明 | データ タイプ | 
string  | The string representation of the object.  | String | 
setDomain (x_min, x_max, y_min, y_max)
| パラメーター | 説明 | データ タイプ | 
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)
| パラメーター | 説明 | データ タイプ | 
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)
| パラメーター | 説明 | データ タイプ | 
m_min  | The minimum m-value.  | Double | 
m_max  | The maximum m-value.  | Double | 
setMFalseOriginAndUnits (false_m, m_units)
| パラメーター | 説明 | データ タイプ | 
false_m  | The false m-value.  | Double | 
m_units  | The m units.  | Double | 
setZDomain (z_min, z_max)
| パラメーター | 説明 | データ タイプ | 
z_min  | The minimum z-value.  | Double | 
z_max  | The maximum z-value.  | Double | 
setZFalseOriginAndUnits (false_z, z_units)
| パラメーター | 説明 | データ タイプ | 
false_z  | The false z-value.  | Double | 
z_units  | The false z units.  | Double | 
コードのサンプル
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("{0} has an unknown spatial reference".format(fc))
    # Otherwise, print out the feature class name and
    # spatial reference
    else:
        print("{0} : {1}".format(fc, spatial_ref.name))