Geoprocessing tool reference > Coverage toolbox > Data Management toolset > Projections toolset > Tools
Project (Coverage) (ArcInfo only) |
|
|
Release 9.2
Last modified February 6, 2007 |
Print all topics in : "Tools" |
NOTE: This tool only works with an ArcInfo license and will only be available in ArcToolbox if you have installed ArcInfo Workstation.
Changes the coordinate system of your coverage including its datum or spheroid.
Learn more about how Project works
Usage tips
-
It can convert a dataset from a spherical coordinate system with angular units (such as Geographic) to a planar coordinate system with linear units. Most Coverage tools, among them Build and Clean, assume you have a planar, two dimensional dataset. So if your dataset is in a geographic coordinate system in decimal degrees (DD, angular units), the Project tool projects your dataset to any suitable projected coordinate system in linear units (meters or feet).
-
A coverage can maintain an explicit definition of the coordinate system in which it is stored. This can be created using the Define Projection tool. If not defined, the projection will be listed as unknown.
-
Output projection information can be specified using a Projection File or from an empty output coverage. The Projection File must contain both input and output projection definitions. Use of a Projection File will override any projection information stored in the data's PRJ file.
-
Clarke 1866 is the default spheroid if it is not inherent to the projection (such as NEWZEALAND_GRID).
-
Do not name an output file the same as the Projection File, even if the Projection File has a .PRJ extension.
-
When projecting a coverage, the Output Coverage can be an existing, empty coverage. The coordinates of the Input Coverage will be projected into the coordinate system defined by the PRJ file of the Output Coverage.
-
Depending on the input and output projection definitions, an arc in the input coverage may need to be clipped into more than one segment while the output coverage is being generated. This will occur whenever an arc encounters the horizon line or crosses the line of longitude opposite the central meridian.
Whenever a vertex is encountered that cannot be projected, the previous vertex will be interpreted as the end of an arc, and the partially projected arc will be written to the output. It is possible for an arc to be split into several arcs if subsequent vertices are encountered that can be projected. In this case, the output retains the original IDs so attributes can be relinked. Examine the illustration below; arcs 2 and 3 will be clipped by the horizon during projection of the line. The output coverage will contain one arc 2 but two arc 3s. In cases such as these, Project will generate arcs having duplicate User-IDs.
-
Whenever a vertex is encountered that cannot be projected, the previous vertex will be interpreted as the end of an arc, and the partially projected arc will be written to the output. It is possible for an arc to be split into several arcs if subsequent vertices are encountered that can be projected.
-
If regions exist in the Input Coverage, regions in the Output Coverage will be preliminary regions. When Build is used to recreate the polygon topology, region topology will also be re-created.
-
If regions exist in the input coverage, regions in the output coverage will be preliminary regions. When the Build tool is used to recreate the polygon topology, region topology will also be re-created.
-
For a PDF document with tables of predefined geographic coordinate system, projected coordinate system, and geographic (datum) transformations, see An overview of map projections.
-
The following environments affect this tool: derivedPrecision, newPrecision, projectCompare, scratchWorkspace, and workspace.
Command line syntax
An overview of the Command Line window
Project_arc <in_cover> <out_cover> <projection_file>
| Parameter | Explanation | Data Type |
| <in_cover> |
The coverage whose coordinates are to be converted. |
Coverage |
| <out_cover> |
The output coverage whose coordinates have been converted to the new coordinate system. The output coverage may exist, but must be empty. |
Coverage |
| <projection_file> |
The name of a text file defining the input and output projection parameters. |
File |
Command line example
project_arc roads roads_utm utm.prj
Scripting syntax
About getting started with writing geoprocessing scripts
Project_arc (in_cover, out_cover, projection_file)
| Parameter | Explanation | Data Type |
| in_cover (Required) |
The coverage whose coordinates are to be converted. |
Coverage |
| out_cover (Required) |
The output coverage whose coordinates have been converted to the new coordinate system. The output coverage may exist, but must be empty. |
Coverage |
| projection_file (Required) |
The name of a text file defining the input and output projection parameters. |
File |
Data types for geoprocessing tool parameters
Script example
import arcgisscripting
gp = arcgisscripting.create()
gp.workspace = "c:/test_data"
gp.toolbox = "arc"
gp.project("usa", "north_america", "albers")