Eye4Software Hydromagic

  Hydrographic Survey Software

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Manage geoid models

In Eye4Software Hydromagic, a geoid model is used to calculate the separation between the local vertical datum and the WGS84 ellipsoidal height returned by the GPS or RTK receiver. Each geoid model is in fact a simple binary file containing separation values in a regularly spaced grid.

The geoid files have the file extension ".geo" and are stored in the "\ProgramData\Hydromagic\Geoids\" folder on your harddrive.
To access the "\ProgramData\Hydromagic\" folder, please select the "Open Program Data Folder..." option from the "Help" menu.

To open the "Manage Geoids" window, select the "Coordinate Systems" => "Manage Geoids" option from the "Tools" menu.
Using this tool, you will be able to add new, remove or alter geoid definitions in the built in database.

Please note that not all geoids are installed by default. Geoid models that are configured, but not installed, are displayed in red. These geoids can be downloaded from our website: http://www.eye4software.com/hydromagic/documentation/geoid-models/

Manage Geoid Models

Geoid list

When clicking an item in the list, its parameters are displayed below the list. You can edit these parameters by clicking the "Modify" button. A geoid model is displayed by the flag of the country where it applies to. If a geoid model applies to multiple countries or regions, a globe is displayed.

Deleting a geoid

You can delete any geoid definition, by selecting an item from the list and clicking the "Delete" button. The software will show a popup to confirm that you are sure you want to delete. When clicking "Yes" the geoid will be deleted.

Modifying a geoid

You can modify a geoid by clicking the "Modify" button after selecting a geoid from the list. After clicking the button, the "OK" button text will change to "Save". Clicking the "Save" button will save the modifications, clicking "Cancel" will keep the old data.

Adding a geoid

To add a new geoid model, click the "Add" button. When adding a new definition, it is required to specify a name for this geoid, as well as the geoid file to be used. Geoid files can be downloaded from our website, or generated using our EGM2008 utility.

Selecting a country is not required, but the country can be used to sort lists by country, if the geoid does not apply to a simple country, just select "Earth", "Europe", "Asia" etc...

Click the "Save" button to store the newly created geoid model, by clicking cancel the input is ignored and you will return to the list.

Video tutorial