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- Access from the toolbar button, as shown in Working with projection in Grid+ 2479915036.
- Access from the File menu, as shown in Working with projection in Grid+ 2479915036.
- Access from the Tools menu, as shown in 2479915036.
When the Projection Settings is selected, the Projection Settings form will appear as shown in
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Figure 4. As mentioned in the information box below, The user is not able to change the coordinate system from this form as Grid+ chooses the WGS84 geographic coordinate system as a default setting. It means that when we create any files from Grid+ and then export them to external files, their coordinates are in Latitude and Longitude. Figure 5 shows coordinates of a spline file when opening with the Notepad editor as an example. The first line of the file provides information on the coordinate system.
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By default Grid+1.2 always works with the Geographic Coordinate System (GCS). This means that its coordinates are longitude and latitude. |
While the projection settings cannot be changed, Grid+ allows the user to convert from the geographic coordinate system for each file layer in the Layer Control panel to the Universal Transverse Mercator (UTM). The user must define the correct UTM zone number for the latitude and longitude location. For example, we have made a grid by using Grid+ for the Caloosahatchee River in Florida, USA. As we have defined it, this river is located in the northern hemisphere UTM zone 17. We now want to convert the grid from the geographic coordinate system to the UTM zone.
To do this, select the grid layer from the Layer Control panel, then Right-mouse click (RMC), select Properties as shown in Working with projection in Grid+ 2479915036. After that Grid Settings form will appear. Select Coordinate System tab, as shown in Working with projection in Grid+ 2479915036, and then click the Convert button. The form for the Coordinate System will pop up, as shown in Working with projection in Grid+ 2479915036. Now, we need to define the correct target coordinate system to which we want to convert. In this case, we select UTM zone 17 in the northern hemisphere, then click OK button. Next, click OK button in the form of Working with projection in Grid+ 2479915036 to close it. Coordinate system conversion is now complete.
Anchor Figure 1 Figure 1
Figure 1. Access projection settings from a toolbar button.
Anchor Figure 2 Figure 2
Figure 2. Access projection settings from File menu.
Anchor Figure 3 Figure 3
Figure 3. Access projection settings from Tools menu.
Anchor Figure 4 Figure 4
Figure 4. Projection Settings form.
Anchor Figure 5 Figure 5
Figure 5. Open a generated file by Grid+ with the Notepad editor.
Anchor Figure 6 Figure 6
Figure 6 6. Select the Properties option of a layer in Layer Control (e.g., Grid layer).
Anchor Figure 7 Figure 7
Figure 7 7. Grid Settings: Coordinate System tab.
Anchor Figure 8 Figure 8
Figure 8 8. Convert Coordinate System.
In this step, we will export the grid to an external grid file. Select the grid layer from the Layer Control panel, then RMC, select Export/Export Grid as shown in Working with projection in Grid+ 2479915036. After that Export Grid form will appear, enter a file name and click Save button, as shown in Working with projection in Grid+ 2479915036.
Opening the grid file with the Notepad editor, we can see that the file contains UTM zone number information (e.g., 17 means that UTM zone 17, in the northern hemisphere) and coordinates values are easting Easting and northing Northing in units of meters, as shown in Working with projection in Grid+ 2479915036. The UTM zone number will be negative for the southern hemisphere, as shown in Working with projection in Grid+ 2479915036.
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For a file that is converted from geographic coordinates to UTM zone by Grid+, do we need to define a coordinate system when opening it by Grid+? The answer is no because Grid+ will get projection information in header lines from the file and locate it in the correct place. |
Anchor Figure 9 Figure 9
Figure 9 9. Export the Grid layer to an external file (1).
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Anchor Figure 10 Figure 10
Figure 10 10. Export the Grid layer to an external file (2).
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Anchor Figure 11 Figure 11
Figure 11 11. Exported grid in the northern hemisphere.
Anchor Figure 12 Figure 12
Figure 12 12. Exported grid in the southern hemisphere.
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When we import a grid that is not the native grid of Grid+ into Grid+ (this grid file does not have projection information in the file), for example, RGF grid (*.grd), we need to define projection for it by selecting right-mouse click on the grid layer in the Layer Control and then selecting Properties, the Grid Settings form will pop up. We select Coordinate System tab, click the Define button. Then, we should select the proper spatial reference, either geographic or UTM coordinate system. Then click the OK button to finish the projection defining step. Next, right-mouse click on that grid layer in the Layer Control, then select Zoom to Layer option, the grid will be located in the right place. |
Updating Overlay Files
In another case, when we open
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an overlay file generated by a CVLGrid such as *.P2D, or from third-party software, for example, a shoreline *.LDB (Delft3D LDB format), we will need to define
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the coordinate system..
In this case, we consider the shoreline as an overlay file so that we will click the Import button from the toolbar, then select Import Overlay as shown in Working with projection in Grid+ 2479915036. The Import Overlay Layer form will pop up. Select the file and click Open button, as shown in Working with projection in Grid+ 2479915036. As a result, a new shoreline layer is added to the Layer Control panel, as shown in Working with projection in Grid+ 2479915036. However, when we RMC on that layer and select Zoom to Layer option, it is not located in the place as we expected. This is because the file does not contain the coordinate system information, so Grid+ does not know where it should be located. This means we must make the shoreline located in the right places in the online background map.
To correctly configure the shoreline location, we must define the correct projection (coordinate system) to the file. RMC on that layer and then select Properties option. The Overlay Properties form will pop up. Select the Coordinate System tab and click the Define button as shown in Working with projection in Grid+ Figure 16. The Coordinate System the form will appear, as shown in Working with projection in Grid+ Figure 17, and we will select the correct projection from this form. The projection should be known by the user. In this case, we select UTM zone 17, northern hemisphere. After that, click OK button. This form will close and go back to the form in Working with projection in Grid+ 2479915036. Next, click OK button to close the form. The process for defining the coordinate system is completed. RMC on the shoreline layer and select Zoom to Layer, and it will be located in the correct location, as shown in Working with projection in Grid+ 2479915036.
Anchor Figure 13 Figure 13
Figure 13 13. Import third-party files with Grid+.
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Anchor Figure 14 Figure 14
Figure 14 14. Select the file to import.
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Anchor Figure 15 Figure 15
Figure 15 15. New shoreline layer added to Layer Control.
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Anchor Figure 16 Figure 16
Figure 16 16. Coordinate System: Define.
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Anchor Figure 17 Figure 17
Figure 17 17. Coordinate System: Define.
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Anchor Figure 18 Figure 18
Figure 18 18. Shoreline located in the correct place after defining a coordinate system.