generate_dtm

Generate DTM

For HiRISE, both NGATE and AATE are used to generate a one meter post DTM. In stereo pairs with substantial relief, and when the stereo images are controlled to the MOLA (either from the Vertical Adjustment or the Absolute Orientation), we use the MOLA DTM as a seed file. This closer approximation to ground-truth greatly increases success of the matcher. In stereo pairs of flat terrain, seeding with MOLA is not necessary.

Load Epipolar Rectified Images

1. From the SOCET SET menu bar, select File > Load Images.

   

2. In the Image Loader window, select <image1>_l for the Left image, and <image1>_r for the Right Image.

   

3. Under View Control Panel settings: Ensure that View = 1 and that Load Point is selected.

   

4. Press Load.

   

5. Press Close.

   

Next Generation Automatic Extraction (NGATE)

From the SOCET SET menu bar, select Extraction > Terrain > Next Generation Automatic Extraction.

Create a New DTM

1. In the NGATE window, select File > Create DTM. (This will bring up the Create DTM window.)

   

2. In the Create DTM window, press the box next to the DTM field.

   

3. In the Select a DTM window, hand enter the name of the DTM to be created as <ProjectName>_NGATE_1m. Then press OK.

   

Images Tab

1. In the Create DTM window: Stay in the Images Tab.

   

2. Under Edit Images, select the epipolar rectified images in the Available list and move them to Selected list via the arrow button. (The epipolar rectified images have _l and _r appended to the image name.)

   

DTM Properties Tab

1. In the Create DTM window: Press the DTM Properties tab.

   

2. Set the X Spacing and Y Spacing to 1.0: Double click in the spacing fields, enter 1.0, and press the enter key.

   

3. Press Draw Polygon to define the DTM Boundary.

   

4. A Draw polygon window will pop-up on the stereo monitor. Move the window over to the console monitor.

   

5. Draw the polygon as follows:

   a. Use the TopoMouse to define the polygon:

   The Left Mouse button measures/samples points. The Right mouse button closes the polygon.

   Note: the first point of the polygon will display ONLY after a second point is measured.

   

   b. Make sure each DTM Boundary point is on the ground.

   c. For stereo pairs of flat terrain, 4 corner points plus 2 points halfway down in the flight direction will suffice.

   d. For stereo pairs of steep terrain, measure a DTM Boundary point at ‘major’ min/max elevations (i.e., at the rim of a large crater, at the crater bottom, etc.)

   e. Establish the boundary within the stereo coverage by ~50 pixels. To estimate this distance:

   i. Bring up the Cursor Editor (under Preferences), and change the Cursor size to 17.

   ii. Move to where you want to place a boundary point.

   iii. Set the image Zoom to 4:1.

   iv. Aligned the cursor with the edge of the stereo coverage, then sample/measure the point.

NGATE Properties Tab

1. Press the NGATE Properties tab.

   

2. Press Strategies… to bring up the list of available NGATE strategies.

   

3. In the NGATE Strategies window, select ngate_HIRISE.strategy in the Available list and move it to Selected list via the arrow button. Then press Close.

   

Seed DTM Tab

1. Press the Seed DTM tab.

   

2. Select <ProjectName>_mola.dth in the Available list and move it to “Selected” list via the arrow button.

   

3. An error message will pop-up to change the AUTOMATIC_RSET value. Press OK.

   

4. Left-Click on the down arrow next to the Automatic option to display a drop-down box of options and select RSET64.

   

5. Finally, press Save to write an initialized DTM to disk. The Create DTM window will automatically close.

   

Run NGATE

NOTE: NGATE will take hours to run when extracting a DTM of the entire HiRISE stereo model. For Guest Facility Users, or others, doing production work, see Appendix: A 5.2 NGATE and AATE Batch Processing for how to run NGATE in batch.

1. Press Start on the NGATE window.

   

2. Upon completion of NGATE, select File > Exit.

   

Convert NGATE DTM to AATE format

Copy/Save NGATE DTM using Interactive Terrain Edit (ITE)

1. From the SOCET SET menu bar, select Extraction > Terrain > Interactive Edit.

   

2. Open the newly created NGATE DTM:

   a. Press the Open DTM icon in the ITE window to bring up the selection window.

   

   b. Select <ProjectName_NGATE_1m from the DTM list. Then press OK.

   

3. On the ITE window, Select File > Save DTM As…`.

   

4. In the selection window, hand enter the name of the output DTM as <ProjectName>_AATE_onepassAfterNGATE_1m. Then press OK.

   

5. On the ITE window, select File > Exit.

   

Update AATE Header File

Edit <ProjectName>_AATE_onepassAfterNGATE_1m.dth to convert it to AATE format. (This is the DTM header file, located in the project’s data folder/directory.)

1. Bring up Windows/File Explorer.

2. Navigate to D:\\DATA\\<ProjectName>. Right-Click on <ProjectName>_AATE_onepassAfterNGATE_1m.dth and select a text editor. At USGS, use SciTE editor.

   

3. Make the following Edits:

   a. Set ATE_METHOD to ADAPTIVE.

   b. Delete ATE_STRATEGIES line.

   c. Delete ATE_SEED_DTMs line.

   d. Set MATCH_OPTION to DOUBLE_MATCH.

   

4. Select File > Save.

   

5. Select File > Exit.

   

6. Close the Windows/File Explorer window.

Replace strategy file for AATE

Replace adapt.strat with adapt.strat.onepassAfterNGATE.strat in the <install_path>\\internal_dbs\\DTM_STRATEGY folder:

1. Bring up a Windows Explorer window.

2. Navigate to C:\\SocetSet_5.6.0\\internal_dbs\\DTM_STRATEGY.

3. Right-Click on adapt.strat and select Delete.

   

4. Right-Click on adapt.strat.onepassAfterNGATE.strat and select Copy.

   

5. Right-Click within the folder and select Paste.

   

6. Right-Click on adapt.strat – Copy.onepassAfterNGATE and select Rename.

   

7. Rename the file adapt.strat.

   

8. Confirm change in extension (press Yes).

   

9. Close Windows/File Explorer window.

Adaptive Automatic Terrain Extraction (AATE)

From the SOCET SET menu bar, select Extraction > Terrain > Automatic Extraction.

###Load NGATE DTM for AATE process

1. From the AATE window, select File > Open DTM….

   

2. Select <ProjectName>_AATE_onepassAfterNGATE_1m in the selection window. Then press OK.

   

Run AATE

NOTE: AATE can take approximately one to two hours to run when using the “onepassAfterNGATE” strategy. For Guest Facility Users, or others, doing production work, see Appendix: A 5.2 NGATE and AATE Batch Processing for how to run AATE in batch**.**

1. Press Start on the AATE window.

   

2. Upon completion of AATE, select File > Exit.