Specifying a Coordinate System

When a spatial image is opened, Geographic Imager will automatically detect whether it has a coordinate system specified in the reference file or not. Before you can transform an image and perform any spatially related operations (like GeoCrop or Mosaic), Geographic Imager needs to know the current coordinate system. If the coordinate system information is not present in the image reference file, it is necessary to specify one.

An image without a coordinate system, but with a valid World reference file.

Specify Source Coordinate System

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Category Folders

The area on the left contains the folders of coordinate systems and subcategories for both recently used coordinate systems and performed searches. Coordinate systems are organized into two categories: Geodetic (unprojected, in latitude and longitude) and Projected. Right-click a folder to rename it or create a new subfolder in it.

Coordinate System List

The coordinate system list displays the name, horizontal datum, point style units, EPSG code, and envelope of each coordinate system. Columns can be resized and sorted alphabetically or numerically. Geodetic and Projected coordinate system categories are sub-divided into world regions (continent/country/state or province) to ease selection. To set a coordinate system, click the desired folder on the left and click the desired coordinate system from the list on the right. Right-click a coordinate system to access a context menu to View Info, Copy Object, Rename Display Name or create New-Object.

Search

All categories and subcategories can be searched by specific or all criteria. Geodetic coordinate systems can be searched by name, horizontal datum, point style units, envelope, and EPSG code. In addition to the previous criteria, projected coordinate systems can be searched by geodetic, projection-type, and projection names. When searching for a coordinate system, the results are displayed in the coordinate system list. Note that the search is always relative to the folder selected category in the coordinate systems folder list. Choose the top-level Coordinate Systems folder to search through all geodetic and projected coordinate systems.

Three subcategories contain specific information:

All: Displays all of the coordinate systems within that category.
Recent: Displays all of the recently used coordinate systems within that category.
Search History: Displays all of the search results for that category.

information The subcategories All, Recent and Search cannot be searched.

information To clear the Recent and Search subcategories, right-click and choose Clear Recent (Search) History.

For more information on projections and coordinate systems, as well as details on editing and adding to the coordinate system database and loading and importing a

coordinate system file or database, see Transformations and Coordinate Systems.

How to specify a coordinate system

Click the Coordinate System link in the Geographic Imager panel or choose Specify Coordinate System from the panel options menu.
The Specify Coordinate System dialog box provides three ways to specify the coordinate system: From File, Same As, and Specify link.

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To set the coordinate system based on a reference file, click the From File button. The Import Source Coordinate System From File dialog box appears. Choose an existing reference file.
To set the coordinate system to be the same as that of another open image with a coordinate system, click the Same As check box and then choose the image to match from the drop-down list. This option is disabled if there are no other referenced images open.
To set a coordinate system from the Geographic Imager data source, click the coordinate system hyperlink. The Specify Source Coordinate System dialog box appears and displays the contents of the current coordinate system database. Navigate the category folders to view available coordinate systems.

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To find more information about the file, click the View coordinate system information button (enabled when a coordinate system is selected).

To remove a coordinate system from an image, click the Clear current coordinate system button.

An image can't be transformed until the coordinate system is known.

Important Notes

information Mac only: When opening a geospatial PDF and a copy of it (i.e. saved as a different name) at the same time, the georeferencing will not be read on the image that is opened second. Referencing will have to be specified manually. This is due to a limitation in Adobe Photoshop.