SpatialReference
Résumé
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.
The SpatialReference object supports equal (==) and not equal (!=) operators for comparing spatial references.
Remarque :
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.
Syntaxe
SpatialReference({item}, {vcs}, {text})
| Nom | Explication | Type de données |
|---|---|---|
|
item (Facultatif) |
The horizontal coordinate system used to create the Create a
Create a
Create a Create a
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 (Facultatif) |
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.
Define the vertical coordinate system using a factory code. |
Variant |
|
text (Facultatif) |
A well-known text (WKT or WKT2 format) string that can be used to define a horizontal and vertical coordinate system. Remarque :When creating a Create a Create a Create a |
String |
Propriétés
| Nom | Explication | Type de données |
|---|---|---|
|
GCS (Lecture seule) |
A projected coordinate system returns a |
SpatialReference |
|
MDomain (Lecture seule) |
The extent of the measure domain. |
String |
|
MFalseOriginAndUnits (Lecture seule) |
The measure false origin and units. |
String |
|
MResolution (Lecture et écriture) |
The measure resolution. |
Double |
|
MTolerance (Lecture et écriture) |
The measure tolerance. |
Double |
|
VCS (Lecture seule) |
If the coordinate system has a vertical coordinate system, the property returns a |
Object |
|
XYResolution (Lecture et écriture) |
The x,y-resolution. |
Double |
|
XYTolerance (Lecture et écriture) |
The x,y-tolerance. |
Double |
|
ZDomain (Lecture seule) |
The extent of the z-domain. |
String |
|
ZFalseOriginAndUnits (Lecture seule) |
The z false origin and units. |
String |
|
ZResolution (Lecture et écriture) |
The z-resolution. |
Double |
|
ZTolerance (Lecture et écriture) |
The z-tolerance. |
Double |
|
abbreviation (Lecture et écriture) |
The abbreviated name of the spatial reference. |
String |
|
alias (Lecture et écriture) |
The alias of the spatial reference. |
String |
|
domain (Lecture seule) |
The extent of the x,y-domain. |
String |
|
factoryCode (Lecture et écriture) |
The factory code or well-known ID (WKID) of the spatial reference. |
Integer |
|
falseOriginAndUnits (Lecture seule) |
The false origin and units. |
String |
|
hasMPrecision (Lecture seule) |
Specifies whether m-value precision information has been defined. |
Boolean |
|
hasXYPrecision (Lecture seule) |
Specifies whether x,y-coordinate precision information has been defined. |
Boolean |
|
hasZPrecision (Lecture seule) |
Specifies whether z-value precision information has been defined. |
Boolean |
|
isHighPrecision (Lecture et écriture) |
Specifies whether the spatial reference has high precision set. |
Boolean |
|
name (Lecture et écriture) |
The name of the spatial reference. |
String |
|
remarks (Lecture et écriture) |
The comment string of the spatial reference. |
String |
|
type (Lecture et écriture) |
Specifies the type of the spatial reference.
|
String |
|
usage (Lecture seule) |
The usage notes. |
String |
|
PCSCode (Lecture et écriture) |
The projected coordinate system code.1 |
Integer |
|
PCSName (Lecture et écriture) |
The projected coordinate system name.1 |
String |
|
azimuth (Lecture et écriture) |
The azimuth of a projected coordinate system.1 |
Double |
|
centralMeridian (Lecture et écriture) |
The central meridian of a projected coordinate system.1 |
Double |
|
centralMeridianInDegrees (Lecture et écriture) |
The central meridian (Lambda0) of a projected coordinate system in degrees.1 |
Double |
|
centralParallel (Lecture et écriture) |
The central parallel of a projected coordinate system.1 |
Double |
|
classification (Lecture seule) |
The classification of a map projection.1 |
String |
|
falseEasting (Lecture et écriture) |
The false easting of a projected coordinate system.1 |
Double |
|
falseNorthing (Lecture et écriture) |
The false northing of a projected coordinate system.1 |
Double |
|
latitudeOf1st (Lecture et écriture) |
The latitude of the first point of a projected coordinate system.1 |
Double |
|
latitudeOf2nd (Lecture et écriture) |
The latitude of the second point of a projected coordinate system.1 |
Double |
|
latitudeOfOrigin (Lecture et écriture) |
The latitude of origin of a projected coordinate system.1 |
Double |
|
linearUnitCode (Lecture et écriture) |
The linear unit code.1 |
Integer |
|
linearUnitName (Lecture et écriture) |
The linear unit name.1 |
String |
|
longitude (Lecture et écriture) |
The longitude value of this prime meridian.1 |
Double |
|
longitudeOf1st (Lecture et écriture) |
The longitude of the first point of a projected coordinate system.1 |
Double |
|
longitudeOf2nd (Lecture et écriture) |
The longitude of the second point of a projected coordinate system.1 |
Double |
|
longitudeOfOrigin (Lecture et écriture) |
The longitude of origin of a projected coordinate system.1 |
Double |
|
metersPerUnit (Lecture seule) |
The meters per linear unit.1 |
Double |
|
projectionCode (Lecture et écriture) |
The projection code.1 |
Integer |
|
projectionName (Lecture et écriture) |
The projection name.1 |
String |
|
scaleFactor (Lecture et écriture) |
The scale factor of a projected coordinate system.1 |
Double |
|
standardParallel1 (Lecture et écriture) |
The first parallel of a projected coordinate system.1 |
Double |
|
standardParallel2 (Lecture et écriture) |
The second parallel of a projected coordinate system.1 |
Double |
|
GCSCode (Lecture et écriture) |
The geographic coordinate system code.2 |
Integer |
|
GCSName (Lecture et écriture) |
The geographic coordinate system name.2 |
String |
|
angularUnitCode (Lecture et écriture) |
The angular unit code.2 |
Integer |
|
angularUnitName (Lecture et écriture) |
The angular unit name.2 |
String |
|
datumCode (Lecture et écriture) |
The datum code.2 |
Integer |
|
datumName (Lecture et écriture) |
The datum name.2 |
String |
|
flattening (Lecture et écriture) |
The flattening ratio of this spheroid.2 |
Double |
|
longitude (Lecture et écriture) |
The longitude value of this prime meridian.2 |
Double |
|
primeMeridianCode (Lecture et écriture) |
The prime meridian code.2 |
Integer |
|
primeMeridianName (Lecture et écriture) |
The prime meridian name.2 |
String |
|
radiansPerUnit (Lecture seule) |
The radians per angular unit.2 |
Double |
|
semiMajorAxis (Lecture et écriture) |
The semi-major axis length of this spheroid.2 |
Double |
|
semiMinorAxis (Lecture et écriture) |
The semi-minor axis length of this spheroid.2 |
Double |
|
spheroidCode (Lecture et écriture) |
The spheroid code.2 |
Integer |
|
spheroidName (Lecture et écriture) |
The spheroid name.2 |
String |
Méthodes
create()
Creates the SpatialReference object using properties.
createFromFile(prj_file)
Creates the SpatialReference object from a projection file.
| Nom | Explication | Type de données |
|---|---|---|
|
prj_file |
The projection file used to populate the |
String |
exportToString({encoding})
Exports the object to its string representation.
| Nom | Explication | Type de données |
|---|---|---|
|
encoding (Facultatif) |
Specifies the encoding of the exported string.
The default value is WKT. |
String |
Valeur de retour
| Type de données | Explication |
|---|---|
|
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
VERTCSsection 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)
| Nom | Explication | Type de données |
|---|---|---|
|
string |
The WKT string representation of the object. |
String |
setDomain(x_min, x_max, y_min, y_max)
Sets the x,y-domain.
| Nom | Explication | Type de données |
|---|---|---|
|
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.
| Nom | Explication | Type de données |
|---|---|---|
|
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.
| Nom | Explication | Type de données |
|---|---|---|
|
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.
| Nom | Explication | Type de données |
|---|---|---|
|
false_m |
The false m-value. |
Double |
|
m_units |
The m-units. |
Double |
setZDomain(z_min, z_max)
Sets the z-domain.
| Nom | Explication | Type de données |
|---|---|---|
|
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.
| Nom | Explication | Type de données |
|---|---|---|
|
false_z |
The false z-value. |
Double |
|
z_units |
The false z-units. |
Double |
Exemple de code
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}")