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
Syntaxe
SpatialReference ({item})| Paramètre | Explication | Type de données |
item | The spatial reference can be created in three ways:
For more information on coordinate system names and factory codes, see geographic_coordinate_systems.pdf and projected_coordinate_systems.pdf files in the ArcGIS Documentation folder. For more information, see Using the spatial reference class. | String |
Propriétés
| Propriété | Explication | Type de données |
| GCS (Lecture seule) | If a projected coordinate system, returns a SpatialReference object for the geographic coordinate system it is based on. If 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 |
| 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 of the spatial reference. | Integer |
| falseOriginAndUnits (Lecture seule) | The false origin and units. | String |
| hasMPrecision (Lecture seule) | Indicates whether or not m-value precision information has been defined. | Boolean |
| hasXYPrecision (Lecture seule) | Indicates whether or not xy precision information has been defined. | Boolean |
| hasZPrecision (Lecture seule) | Indicates whether or not z-value precision information has been defined. | Boolean |
| isHighPrecision (Lecture/écriture) | Indicates whether or not 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 ()
Valeur renvoyée
| 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
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))