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Coordinate System
To specify the Coordinate System for the Job:
- In Projection select the projection to be used from the drop-down list. Initially the list is empty. Click
to open Pre Defined CS dialog and activate projections necessary for work.
- Select the Use Grid/Ground check box to enable transformation to ground coordinates for surveying. Click
to open Grid/Ground Parameters dialog and set transformation parameters. Find out more on Grid to Ground transformation. After closing the Coordinate System dialog, the default display system will be Ground.
- In Datum specify the datum as required for the projection selected. Select the datum from the drop-down list.
If NAD 27 datum is selected, you can use one of the following:
- Predefined parameters; in this case the application will apply parameters NAD27 from the its own database for transformation between NAD27 and NAD83_NO_TRANS datums
- NADCON; in this case the application will apply the Federal standard (NADCON program) for NAD 27 to NAD83_NO_TRANS datum transformations
If ATS77(CSRS), NAD 27(CSRS) or NAD 83(CSRS) datum is selected, you can use one of the following:
- Predefined parameters; in this case the application will apply parameters ATS77(CSRS), NAD 27(CSRS) or NAD 83(CSRS) from its own database for transformation between the datum and NAD83_NO_TRANS datums
- File(N/A); in this case the application will apply datum data from the file. Click
to select the required *.gsb file.
Note: The NAD83 datum has three independent realizations in MAGNET Field with respect to the WGS84 datum: NAD83, NAD83(ITRF96) and NAD83_NO_TRANS. More...
Click
to add a custom datum if necessary. More...
- Select Geoid from the drop-down list. The job will refer to the selected geoid file to convert ellipsoidal heights to elevations. Click
to add the geoid to the list. More...
Optionally, when ATS77(CSRS), or NAD 27(CSRS), or NAD 83(CSRS) datum is selected and you specified a desired *.gsb file for datum transformation, you can choose the transformation direction. To do this, select the Advanced CSRS Options from the pop-up menu that displays by clicking
in the top left corner.
Pre Defined CS
The Pre Defined CS dialog contains a list of cataloged projections divided by regions, that can be chosen for use in the job.
To add a desired projection to the list in the Coordinate System dialog:
In the Pre-Defined panel:
- Click the region node to expand the tree of available projections, and use the scroll bar to view the full list of projections.
- Highlight the name of the desired projection.
- Use the arrow button to select the chosen projection in the Pre-Defined panel and insert it into the Active panel.
- Repeat the steps to add other projections.
- Create a custom projection to the list of pre-defined ones by clicking the Custom button. More...
In the Active panel:
- View all active projections.
- Use
to delete a highlighted projection from the Active panel if required.
- Click
to add the active projections to the drop-down list in the Coordinate System dialog.
Custom Projections
Besides projections that are predefined in MAGNET Field, it is possible to use custom grid projections. Custom projections can be of the following types:
- User-defined - for which parameters are entered manually.
- Projections obtained by the rover along with corrections data from the base station.
Note: The GNSS rover receiver can obtain projection/datum parameters from the base station when a Network RTK configuration is used and the RTCM 3.* format is selected for data corrections.
The Custom Projections dialog contains a list of custom (user-defined) projections. Projections obtained from the base station are marked with the
icon in the list.
- Click the Add button to create a new custom projection and add it to the list. More...
- Click the Edit button to change the parameters of the highlighted projection. This can be done for user-defined projections only.
- If an obtained projection is selected, the Edit button is displayed as View. The parameters of such a projection are read-only.
- Click the Delete button to delete a highlighted projection from the list and file system.
Custom Projection - 1
To create a new custom projection:
- Enter a Name for the new projection.
- Select a Type from the list of sample projections.
- Select a Datum from the displayed list of datums, or click
to create a custom one (more...) and then select it.
- Enter the Region to which the projection belongs. If no region is specified, it will be added to the Global list.
- Enter a description (Note) for the projection.
- Click Next to enter the new projection specifications depending on the selected sample projection type. More...
Custom Projection - 2
Depending on the Type of projection selected, you are prompted to fill in some of the following fields.
- Enter the latitude (Lat0) and longitude (Lon0) of a point chosen as the origin on the central meridian of the custom projection.
- Enter the false Easting (East0 or E0) and Northing (North0 or N0) of the origin for the projection. These constant values are added to all negative Eastings and Northings to get only positive values of Easting and Northing.
- Enter the Scale that sets a constant scale factor along the central meridian of the custom projection.
- Enter the longitude of Central Meridian for the projection.
- Enter the North and South latitudes bounding the area of the custom projection (NorthLat and SouthLat).
- Enter the azimuth of the axis (AxisAzimuth) for the projection.
- Click
to create the new projection and add it to the Projection list.
Note: The Latitudes are positive for the Northern Hemisphere, and negative for the Southern Hemisphere. The Longitudes are positive for Eastern directions and negative for Western directions relative to the GMT line.
Custom Datums
Besides datums that are predefined in MAGNET Field, it is possible to use the custom ones. Custom datums can be of the following types:
- User-defined - for which parameters are entered manually.
- Datums obtained by the rover along with corrections data from the base station.
Note: The GNSS rover receiver can obtain projection/datum parameters from the base station when a Network RTK configuration is used and the RTCM 3.* format is selected for data corrections.
The Custom Datums dialog contains a list of custom (user-defined) datums. Datums obtained from the base station are marked with the
icon in the list.
- Click the Add button to create a new custom datum and add it to the list. More...
- Click the Edit button to change a datum that is highlighted in the list.
- If an obtained datum is selected, the Edit button is displayed as View. The parameters of such a datum are read-only.
- Click the Delete button to delete a highlighted datum from the list and file system.
Custom Datum - 1
To create a new custom datum:
- Enter a Name for the new datum.
- Select an Ellipsoid from the displayed list of ellipsoids, or click
to create a custom one (more...) and then select it.
- Select a coordinates transformation Method.
- Enter a description (Note) for the datum.
- Select an Alias for a new datum.
- Click Next to enter transformation parameters to convert from WGS84 to the new datum. More...
Custom Datum - 2
MAGNET Field uses the seven-parameters Helmert Transformation Strict Formula for datum transformation.
To create a custom datum:
- In Offsets, enter the Datum to Space (WGS84) offsets: dX, dY, dZ.
- In Rotations, enter the Datum to Space (WGS84) rotations: rX, rY, rZ, in seconds.
- In Pivot Pt, enter the coordinates of the pivot point X0, Y0, Z0 (available if Molodensky (with Pivot Point) method of coordinates transformation is selected in the Custom Datum - 1 dialog.
- Enter the Scale in parts per million (ppm).
- Select the Direction of coordinates transformation.
- Click
to create the new datum and add it to the Datum list.
Custom Ellipsoids
This dialog contains a list of custom (user-defined) ellipsoids.
- Initially the Ellipsoid list is empty.
- Click the Add button to create a new custom ellipsoid and add it to the list. More...
- Click the Edit button to change an ellipsoid that was added to the list.
- Click the Delete button to delete a highlighted ellipsoid from the list.
Custom Ellipsoid
To create a custom ellipsoid:
- Enter a Name for the ellipsoid.
-
Change the values of ellipsoid semi-major equatorial axis (A) and inverse flattening (1/F) as required.
Note: By default, the A and 1/F fields contains the values for the most common reference ellipsoid defined by WGS84.
- In Note, enter a description for the ellipsoid.
- Click
to create the new ellipsoid and add it to the list of all the available Ellipsoids.
Advanced CSRS Options
In this dialog you can choose the transformation direction between ATS77(CSRS), NAD 27(CSRS) or NAD 83(CSRS) and NAD83_NO_TRANS datums.
Geoids List
Geoid is the physical reference surface of the Earth. Its shape reflects the distribution of mass inside the Earth. Geoid undulations are important for converting GPS-derived ellipsoidal height differences to orthometric height differences (elevations).
The Geoids List dialog contains a list of Geoids available for selection: the Name and Full Path and Type.
- Initially the Geoid List is empty.
-
Click the Add button to add a new geoid to the list. More...
Note: Install the geoid file on the disk prior to adding it to the list. Some geoid files can be installed into the Geoids folder during MAGNET Field installation. They are provided with the installation program as Geoid File Format (.gff) files.
- Click the Edit button to change a geoid that was added to the list.
- Click the Remove button to delete a highlighted geoid from the list.
Add / Edit Geoid
In the Add / Edit Geoid dialog, select a Geoid file from disk and see the boundaries for the geoid. After being chosen, the geoid file appears in the Geoids List dialog.
To add a geoid to the geoids list:
- Select the Geoid Format of the geoid file to load.
- Click Browse to navigate to the desired file in the selected geoid format and select it.
- After the geoid is chosen,
displays the path to the file.
- After the geoid is chosen, you can see the boundary of the geoid application: the longitudes and latitudes of the north-west
and south-east
corners of the geoid boundary.
- Click
to add the selected geoid to the list of all the available Geoids in the jobs.
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