Unlike the above, where the list of elements from the EPSG database appears by default, only the list of user transformations is displayed. These datum shifts are based on geoid models with their own format. Hence, no datum shift proposed by the OGP in its EPSG database is admitted.
Each line of the list includes the code and name of the datum shift separated by a colon.
In the Search By section you can filter the query data by Code and Name. You have to enter the search string in the box on the right and click the button . In the case of searching by code, it will only display the result if the code in question exists in the database, whereas in the search by name, it will display all the datum shifts whose name contains the string entered.
By double-clicking a datum shift on the list, its properties are displayed: Description, Source Datum, Target Datum and File.
New datum shifts can be created. The data requested are:
Code:An alphanumeric string of up to 16 characters is allowed.
Name:An alphanumeric string of up to 64 characters is allowed.
Description: Optional field. An alphanumeric string of up to 128 characters is allowed.
Source Datum: The datum WGS 84 (code EPSG 6326) is established by default.
Target Datum: Select from the list displayed by clicking the button .
Transformation Parameters: Lets you select the geoid model file the datum transformation is based on. This file is binary and has the extension *.GDE.
TcpMDT
. In the case of searching by code, it will only display the result if the code in question exists in the database, whereas in the search by name, it will display all the datum shifts whose name contains the string entered.
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