Using the Extract Terrain to MPT Tool

To extract terrain to MPT:

1.     On the Tools tab, in the Extract Terrain group, click Extract to MPT. The Extract Terrain to MPT tool opens.

2.     Create a high resolution area polygon by doing the following:

a.     Click Add.

b.     In the 3D Window, click in the required locations to place the polygon points. You must place at least three points.

c.     Right-click to finish the polygon creation.

d.     Perform any of the following editing operations if required:

·         Move a node – Click Edit. Then in the 3D Window, place the cursor over one of the polygon’s nodes. The node turns blue, and the cursor changes to Move mode . Click the node and drag it to the required location in the XY Plane. Release the mouse button to set the node at the current location.

·         Add a node – Click Edit. Then in the 3D Window, place the cursor over one of the polygon’s lines. Where a node can be added, a red node appears on the line and the cursor changes to Add Node mode . Click to add a node, and then drag it to the required location.

·         Delete a node – Click Edit. Then in the 3D Window, place the cursor over the node you want to delete. The node turns blue, and the cursor changes to Move mode . Right-click, and select Delete Node from the shortcut menu.

Note:        If you want to remove the polygon and create a new one, click Remove and repeat steps a-d.

e.     Set the quality of the high-resolution area by selecting a Unit Per Pixel value from the dropdown list.

Note:    The Unit Per Pixel list of values is created from the terrain database (MPT file) pyramid of resolutions.

3.     Type the Length of and resolution of the Medium Resolution Area Square. The medium resolution area square always surrounds the high-resolution polygon. Type 0 to remove the square. The Unit per Pixel value must be higher (lower resolution) than the value set in the High-resolution polygon.

4.     Select the Low Resolution Area Unit Per Pixel value.

The Low Resolution Area always covers the entire MPT database to ensure that the current project will run.

Note:        It is recommended to set a medium resolution area around the High-resolution polygon to get a smooth transition between the high-quality terrain and the very low-resolution background. It is recommended that the medium resolution be four levels higher than the selected high-resolution. The Low Resolution Area can be set to the worst resolution to reduce the size of the extracted MPT.

5.     Click Scan to get a better estimation of the size of the new MPT. If you want to stop the scanning process, click Abort.

Note:        While setting the size and resolutions of the different areas, the Extract Terrain tool displays an estimated size of the new MPT file based on a calculation (multiplication of the areas and the selected resolutions). After clicking the Scan option, the Extract Terrain tool scans the three areas and calculates the size based on the actual resolution of the terrain in these areas. The final size of the new MPT file can be distinctly different from the calculated and scan sizes if the original MPT file has many areas with different resolutions.

6.     Select the name of the extracted MPT file by typing a valid file name, or click the Browse button and select an existing directory and file name on your system.

7.     Click Create MPT to start downloading and creating the new MPT file.

8.     Click Abort to stop the creation process, or Pause and Resume to temporarily halt the process and resume it from the same location.