## Summary

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.

## Discussion

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.

##### Note:

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}.

## Syntax

SpatialReference ({item}, {vcs})

Parameter | Explanation | Data Type |

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. - Using a projection file (.prj)
`sr = arcpy.SpatialReference("c:/coordsystems/NAD 1983.prj")` - Using the name of the coordinate system
`sr = arcpy.SpatialReference("Hawaii Albers Equal Area Conic")` - 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)` - Using a well-known text string representation
`# String below is representation 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)`
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. - Using names
`sr = arcpy.SpatialReference("Hawaii Albers Equal Area Conic", "MSL (Height)")` - Using factory codes
`# 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)` - Using a well-known text string representation. Note that the vcs argument is not used, and the VCS is defined in the VERTCS section of the WKT.
`# String below is representation 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)`
| Variant |

## Properties

Property | Explanation | Data Type |

GCS (Read Only) | 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 (Read Only) | The extent of the measure domain. | String |

MFalseOriginAndUnits (Read Only) | The measure false origin and units. | String |

MResolution (Read and Write) | The measure resolution. | Double |

MTolerance (Read and Write) | The measure tolerance. | Double |

VCS (Read Only) | 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 (Read and Write) | The xy resolution. | Double |

XYTolerance (Read and Write) | The xy tolerance. | Double |

ZDomain (Read Only) | The extent of the z domain. | String |

ZFalseOriginAndUnits (Read Only) | The z false origin and units. | String |

ZResolution (Read and Write) | The z resolution property. | Double |

ZTolerance (Read and Write) | The z-tolerance property. | Double |

abbreviation (Read and Write) | The abbreviated name of the spatial reference. | String |

alias (Read and Write) | The alias of the spatial reference. | String |

domain (Read Only) | The extent of the xy domain. | String |

factoryCode (Read and Write) | The factory code or well-known ID (WKID) of the spatial reference. | Integer |

falseOriginAndUnits (Read Only) | The false origin and units. | String |

hasMPrecision (Read Only) | Indicates whether m-value precision information has been defined. | Boolean |

hasXYPrecision (Read Only) | Indicates whether xy precision information has been defined. | Boolean |

hasZPrecision (Read Only) | Indicates whether z-value precision information has been defined. | Boolean |

isHighPrecision (Read and Write) | Indicates whether the spatial reference has high precision set. | Boolean |

name (Read and Write) | The name of the spatial reference. | String |

remarks (Read and Write) | The comment string of the spatial reference. | String |

type (Read and Write) | The type of the spatial reference. - Geographic—A geographic coordinate system.
- Projected— A projected coordinate system.
| String |

usage (Read Only) | The usage notes. | String |

PCSCode (Read and Write) | The projected coordinate system code. | Integer |

PCSName (Read and Write) | The projected coordinate system name. | String |

azimuth (Read and Write) | The azimuth of a projected coordinate system. | Double |

centralMeridian (Read and Write) | The central meridian of a projected coordinate system. | Double |

centralMeridianInDegrees (Read and Write) | The central meridian (Lambda0) of a projected coordinate system in degrees. | Double |

centralParallel (Read and Write) | The central parallel of a projected coordinate system. | Double |

classification (Read Only) | The classification of a map projection. | String |

falseEasting (Read and Write) | The false easting of a projected coordinate system. | Double |

falseNorthing (Read and Write) | The false northing of a projected coordinate system. | Double |

latitudeOf1st (Read and Write) | The latitude of the first point of a projected coordinate system. | Double |

latitudeOf2nd (Read and Write) | The latitude of the second point of a projected coordinate system. | Double |

latitudeOfOrigin (Read and Write) | The latitude of origin of a projected coordinate system. | Double |

linearUnitCode (Read and Write) | The linear unit code. | Integer |

linearUnitName (Read and Write) | The linear unit name. | String |

longitude (Read and Write) | The longitude value of this prime meridian. | Double |

longitudeOf1st (Read and Write) | The longitude of the first point of a projected coordinate system. | Double |

longitudeOf2nd (Read and Write) | The longitude of the second point of a projected coordinate system. | Double |

longitudeOfOrigin (Read and Write) | The longitude of origin of a projected coordinate system. | Double |

metersPerUnit (Read Only) | The meters per linear unit. | Double |

projectionCode (Read and Write) | The projection code. | Integer |

projectionName (Read and Write) | The projection name. | String |

scaleFactor (Read and Write) | The scale factor of a projected coordinate system. | Double |

standardParallel1 (Read and Write) | The first parallel of a projected coordinate system. | Double |

standardParallel2 (Read and Write) | The second parallel of a projected coordinate system. | Double |

GCSCode (Read and Write) | The geographic coordinate system code. | Integer |

GCSName (Read and Write) | The geographic coordinate system name. | String |

angularUnitCode (Read and Write) | The angular unit code. | Integer |

angularUnitName (Read and Write) | The angular unit name. | String |

datumCode (Read and Write) | The datum code. | Integer |

datumName (Read and Write) | The datum name. | String |

flattening (Read and Write) | The flattening ratio of this spheroid. | Double |

longitude (Read and Write) | The longitude value of this prime meridian. | Double |

primeMeridianCode (Read and Write) | The prime meridian code. | Integer |

primeMeridianName (Read and Write) | The prime meridian name. | String |

radiansPerUnit (Read Only) | The radians per angular unit. | Double |

semiMajorAxis (Read and Write) | The semi-major axis length of this spheroid. | Double |

semiMinorAxis (Read and Write) | The semi-minor axis length of this spheroid. | Double |

spheroidCode (Read and Write) | The spheroid code. | Integer |

spheroidName (Read and Write) | The spheroid name. | String |

## Method Overview

Method | Explanation |

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. |

## Methods

create ()

createFromFile (prj_file)

Parameter | Explanation | Data Type |

prj_file | The projection file used to populate the spatial reference object. | String |

exportToString ()

Data Type | Explanation |

String | The string representation of the object. |

loadFromString (string)

Parameter | Explanation | Data Type |

string | The string representation of the object. | String |

setDomain (x_min, x_max, y_min, y_max)

Parameter | Explanation | Data Type |

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 | Explanation | Data Type |

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 | Explanation | Data Type |

m_min | The minimum m-value. | Double |

m_max | The maximum m-value. | Double |

setMFalseOriginAndUnits (false_m, m_units)

Parameter | Explanation | Data Type |

false_m | The false m-value. | Double |

m_units | The m units. | Double |

setZDomain (z_min, z_max)

Parameter | Explanation | Data Type |

z_min | The minimum z-value. | Double |

z_max | The maximum z-value. | Double |

setZFalseOriginAndUnits (false_z, z_units)

Parameter | Explanation | Data Type |

false_z | The false z-value. | Double |

z_units | The false z units. | Double |

## Code sample

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("{} has an unknown spatial reference".format(fc))
# Otherwise, print out the feature class name and spatial reference
else:
print("{} : {}".format(fc, spatial_ref.name))
```