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
Les étendues XY, Z et M ne correspondent pas aux domaines de référence spatiale. Les domaines XY, Z et M d'une référence spatiale définissent la plage valide de valeurs de coordonnées pouvant être stockées dans une classe d'entités. Les étendues de la classe d’entités reflètent la plage réelle des valeurs de coordonnées présentes dans la classe d’entités. Ces étendues ne peuvent pas être plus importantes que les domaines.
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.
Syntaxe
SpatialReference ({item}, {vcs})
Paramètre | Explication | Type de données |
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 |
Propriétés
Propriété | Explication | Type de données |
GCS (Lecture seule) | 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 (Lecture seule) | The extent of the measure domain. | String |
MFalseOriginAndUnits (Lecture seule) | The measure false origin and units. | String |
MResolution (Lecture/écriture) | The measure resolution. | Double |
MTolerance (Lecture/écriture) | The measure tolerance. | Double |
VCS (Lecture seule) | 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 (Lecture/écriture) | The xy resolution. | Double |
XYTolerance (Lecture/écriture) | The xy tolerance. | Double |
ZDomain (Lecture seule) | The extent of the z domain. | String |
ZFalseOriginAndUnits (Lecture seule) | The z false origin and units. | String |
ZResolution (Lecture/écriture) | The z resolution property. | Double |
ZTolerance (Lecture/écriture) | The z-tolerance property. | Double |
abbreviation (Lecture/écriture) | The abbreviated name of the spatial reference. | String |
alias (Lecture/écriture) | The alias of the spatial reference. | String |
domain (Lecture seule) | The extent of the xy domain. | String |
factoryCode (Lecture/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) | Indicates whether m-value precision information has been defined. | Boolean |
hasXYPrecision (Lecture seule) | Indicates whether xy precision information has been defined. | Boolean |
hasZPrecision (Lecture seule) | Indicates whether z-value precision information has been defined. | Boolean |
isHighPrecision (Lecture/écriture) | Indicates whether the spatial reference has high precision set. | Boolean |
name (Lecture/écriture) | The name of the spatial reference. | String |
remarks (Lecture/écriture) | The comment string of the spatial reference. | String |
type (Lecture/écriture) | The type of the spatial reference.
| String |
usage (Lecture seule) | The usage notes. | String |
PCSCode (Lecture/écriture) | The projected coordinate system code.1 | Integer |
PCSName (Lecture/écriture) | The projected coordinate system name.1 | String |
azimuth (Lecture/écriture) | The azimuth of a projected coordinate system.1 | Double |
centralMeridian (Lecture/écriture) | The central meridian of a projected coordinate system.1 | Double |
centralMeridianInDegrees (Lecture/écriture) | The central meridian (Lambda0) of a projected coordinate system in degrees.1 | Double |
centralParallel (Lecture/écriture) | The central parallel of a projected coordinate system.1 | Double |
classification (Lecture seule) | The classification of a map projection.1 | String |
falseEasting (Lecture/écriture) | The false easting of a projected coordinate system.1 | Double |
falseNorthing (Lecture/écriture) | The false northing of a projected coordinate system.1 | Double |
latitudeOf1st (Lecture/écriture) | The latitude of the first point of a projected coordinate system.1 | Double |
latitudeOf2nd (Lecture/écriture) | The latitude of the second point of a projected coordinate system.1 | Double |
latitudeOfOrigin (Lecture/écriture) | The latitude of origin of a projected coordinate system.1 | Double |
linearUnitCode (Lecture/écriture) | The linear unit code.1 | Integer |
linearUnitName (Lecture/écriture) | The linear unit name.1 | String |
longitude (Lecture/écriture) | The longitude value of this prime meridian.1 | Double |
longitudeOf1st (Lecture/écriture) | The longitude of the first point of a projected coordinate system.1 | Double |
longitudeOf2nd (Lecture/écriture) | The longitude of the second point of a projected coordinate system.1 | Double |
longitudeOfOrigin (Lecture/écriture) | The longitude of origin of a projected coordinate system.1 | Double |
metersPerUnit (Lecture seule) | The meters per linear unit.1 | Double |
projectionCode (Lecture/écriture) | The projection code.1 | Integer |
projectionName (Lecture/écriture) | The projection name.1 | String |
scaleFactor (Lecture/écriture) | The scale factor of a projected coordinate system.1 | Double |
standardParallel1 (Lecture/écriture) | The first parallel of a projected coordinate system.1 | Double |
standardParallel2 (Lecture/écriture) | The second parallel of a projected coordinate system.1 | Double |
GCSCode (Lecture/écriture) | Code du système de coordonnées géographiques.2 | Integer |
GCSName (Lecture/écriture) | Nom du système de coordonnées géographiques.2 | String |
angularUnitCode (Lecture/écriture) | Code d'unité angulaire.2 | Integer |
angularUnitName (Lecture/écriture) | Nom d'unité angulaire.2 | String |
datumCode (Lecture/écriture) | Code du datum.2 | Integer |
datumName (Lecture/écriture) | Nom du datum.2 | String |
flattening (Lecture/écriture) | Coefficient d'aplatissement de cette sphéroïde.2 | Double |
longitude (Lecture/écriture) | Valeur de longitude de ce méridien principal.2 | Double |
primeMeridianCode (Lecture/écriture) | Code de méridien principal.2 | Integer |
primeMeridianName (Lecture/écriture) | Nom du méridien principal.2 | String |
radiansPerUnit (Lecture seule) | Radians par unité angulaire.2 | Double |
semiMajorAxis (Lecture/écriture) | Longueur du demi-grand axe de ce sphéroïde.2 | Double |
semiMinorAxis (Lecture/écriture) | Longueur du demi-petit axe de ce sphéroïde.2 | Double |
spheroidCode (Lecture/écriture) | Code du sphéroïde.2 | Integer |
spheroidName (Lecture/écriture) | Nom du sphéroïde.2 | String |
Vue d’ensemble des méthodes
Méthode | Explication |
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. |
Méthodes
create ()
createFromFile (prj_file)
Paramètre | Explication | Type de données |
prj_file | The projection file used to populate the spatial reference object. | String |
exportToString ()
Type de données | Explication |
String | The string representation of the object. |
loadFromString (string)
Paramètre | Explication | Type de données |
string | The string representation of the object. | String |
setDomain (x_min, x_max, y_min, y_max)
Paramètre | 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)
Paramètre | Explication | Type de données |
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)
Paramètre | Explication | Type de données |
m_min | The minimum m-value. | Double |
m_max | The maximum m-value. | Double |
setMFalseOriginAndUnits (false_m, m_units)
Paramètre | Explication | Type de données |
false_m | The false m-value. | Double |
m_units | The m units. | Double |
setZDomain (z_min, z_max)
Paramètre | Explication | Type de données |
z_min | The minimum z-value. | Double |
z_max | The maximum z-value. | Double |
setZFalseOriginAndUnits (false_z, z_units)
Paramètre | 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("{} has an unknown spatial reference".format(fc))
# Otherwise, print out the feature class name and spatial reference
else:
print("{} : {}".format(fc, spatial_ref.name))
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