ArcGIS Desktop

  • ArcGIS Pro
  • ArcMap

  • My Profile
  • Help
  • Sign Out
ArcGIS Desktop

ArcGIS Online

The mapping platform for your organization

ArcGIS Desktop

A complete professional GIS

ArcGIS Enterprise

GIS in your enterprise

ArcGIS Developers

Tools to build location-aware apps

ArcGIS Solutions

Free template maps and apps for your industry

ArcGIS Marketplace

Get apps and data for your organization

  • Documentation
  • Support
Esri
  • Sign In
user
  • My Profile
  • Sign Out

ArcMap

  • Home
  • Get Started
  • Map
  • Analyze
  • Manage Data
  • Tools
  • Extensions

Define Projection

Available with Advanced license.

  • Summary
  • Usage
  • Syntax
  • Code sample
  • Environments
  • Licensing information

Summary

Records the coordinate system information of the Input Coverage including any associated projection parameters, such as datum and spheroid.

It creates or modifies the Input Coverage's projection definition file (PRJ) that stores the projection parameters.

Learn more about how Define Projection works

Usage

  • Can be used if the input dataset or feature class does not have a projection defined. If the input dataset or feature class already has a projection defined, a warning will be raised but the tool will execute successfully.

  • To actually project the dataset or transform the datum or spheroid, you need to use the Project tool, which requires that your dataset have a PRJ file.

  • Define Projection will not change the coordinates of the output dataset. To project a dataset from one projection to another, you must use Project.

  • To find tables of predefined geographic coordinate system, projected coordinate system, and geographic (datum) transformations, see An overview of map projections.

Syntax

arcpy.arc.DefineProjection(in_cover, projection_file)
ParameterExplanationData Type
in_cover

The coverage for which the projection information is being defined.

Coverage
projection_file

The name of a text file defining the input projection parameters.

File

Code sample

DefineProjection example (stand-alone script)

The following stand-alone script demonstrates how to define the projection on a global coverage. The coverage is stored in geographic coordinates.

# Name: DefineProjection_Example.py
# Description: Defines the projection of a global coverage
# Requirements: ArcInfo Workstation

# Import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data"

# Set local variables
inCover = "worldgrat"
projectionFile = "newgeo.prj"

# Execute DefineProjection
arcpy.DefineProjection_arc (inCover, projectionFile)

Environments

  • Current Workspace
  • Level Of Comparison Between Projection Files
  • Precision For Derived Coverages
  • Precision For New Coverages
  • Scratch Workspace

Licensing information

  • Basic: No
  • Standard: No
  • Advanced: Requires ArcInfo Workstation installed

Related topics

  • Supported map projections
  • About map projections
  • What are geographic coordinate systems?
  • What are projected coordinate systems?
  • Geographic transformation methods
  • An overview of the Projections toolset
  • Define Projection
  • Project
  • Transform
  • What is a coverage?
  • Storing coordinates
  • Determining a map's projection

ArcGIS Desktop

  • Home
  • Documentation
  • Support

ArcGIS

  • ArcGIS Online
  • ArcGIS Desktop
  • ArcGIS Enterprise
  • ArcGIS
  • ArcGIS Developer
  • ArcGIS Solutions
  • ArcGIS Marketplace

About Esri

  • About Us
  • Careers
  • Esri Blog
  • User Conference
  • Developer Summit
Esri
Tell us what you think.
Copyright © 2021 Esri. | Privacy | Legal