edit_dtm

#Edit DTM

Use Interactive Terrain Edit (ITE) to display and edit DTMs. ITE provides post (point), geomorphic (line), and area editing tools. The Post Editor allows post-by-post review and edit. It is used for detailed editing of small areas. The Area Editor changes all posts within an area delineated by a polygon. It is used for smoothing, plane fill, interpolation, etc. The Geomorphic editor forces a DTM to conform to breaklines such as ridges and drains, that you draw.

The scope of this section is not to show how to use all the tools, but to suggest a few that we find most useful. What follows is our training guide for ITE. It is self-contained and steps you through loading a project, loading images, stereo display options needed for editing, setting graphical display and cursor preferences, ITE options and tips, and a FAQ section.

Loading a Project

• Start SOCET SET.

• Open a current project: SOCET SET > File > Load Project

• Select the project from the window

  

• Open the Image Loader Window: SOCET SET > “File” > “Load Images”

  

The following window will appear. Select the Left and Right Images to display. Make sure that Load Point is selected at the bottom of the window, under View Control Panel settings. Use this interface to load the epipolar rectified Left and Right images into View 1.

Set the stereo display, planar monitor settings

Below is an example of the settings typically used for View 1 during an editing session. (These are on the View 1 window.) The standard settings for the planar monitor, stereo display are highlighted with an arrow.

Start Interactive Terrain Edit (ITE)

• Open Interactive Terrain Edit (ITE): SOCET SET > Extraction > Terrain > Interactive Edit

  

• The following window will open.

  

• Open or load the DTM with File > Open, or press the open file icon

Setting graphical display options

Open the Graphic Display Preference window for ITE: Select ITE > Options > Preferences (see Method 1). A faster, alternate method to open the Graphic Display Preference window is by clicking on the icon button toolbar along the top of the ITE Window.

Method 1

Press the Setup DTM Graphics Icon button (see Method 2)

Method 2

Shown below is the ITE Window toolbar.

Select the Icon shown below from the toolbar. This has the same effect as clicking on ITE > Options > Preferences

Shown below is the ITE Graphic Preferences window: The settings shown in this example are typical settings used for HiRISE DTM editing.

After setting your DTM graphic preferences, press the icon indicated below to draw the graphics in View 1

Setting cursor preferences

To assist in setting editing preferences, open the Cursor preference window. Select SOCET > Preferences > Cursor/Graticule Editor. Use this to save or load a cursor editor style. While editing a DTM using ITE, the cursor style keeps resetting to the default cursor style which may not be an individual user’s preferred cursor style. After setting the cursor editor style options, use File > Save Cursor to save your own style, and use File > Load to open a previously save cursor editor style.

Below is an example of a desktop, with SOCET SET/Interactive Terrain Edit initiated, and other options and preferences discussed above available.

##SOCET SET Interactive Terrain Editing

Post Editing – Use this editing function when you want to adjust the elevation of the individual posts. Beware – this is a time-consuming editing choice, but it allows for high accuracy in setting individual post elevation.

Press the icon indicated below from the ITE Toolbar

The following window will open

For this editor, change the graphic display Mode (under the Preferences window) to Dots, Icons, or Editable Contours & Dots – in other words, a graphical display in which you can identify the individual posts. Click on “Grab Post” to snap to the post you want to adjust. Use the cursor arrows to move from post to post. To release the post, click again on “GRAB POST” and the cursor will release the post. Be sure to intermittently toggle the graphical display between Off/Limited at View 1 to verify that you are “on the ground”. You can also use the “snap to ground” button on the cursor to quickly move the post to ground. Visually verify that the post was moved to ground. Don’t just rely on the software.

Area Editing – Use this editing feature to adjust the elevation for a group of posts. There are many available functions within this edit feature. Below are 3 of the most commonly used.

Press the icon indicated below from the ITE Toolbar: Using the TopoMouse, draw a polygon around the area to be edited.

This area editor is great for spikes (where one or more posts are obviously off of the ground and the surrounding posts are generally on the ground). Just draw a polygon around the spike and the software will interpolate the elevation of the posts inside the polygon from those directly outside of the polygon. However, this editor rarely works against the outer edge of the DTM.

Use this area editor whenever a general smoothing of an area of post elevations is desired. It works well when the posts are generally close to the ground, but there is artificial noise. Use the “Redo” button for as many repetitions as desired. This is a good follow up to an “Interpolate_1st_order” area edit. However, if your post are “off the ground” to begin with, this area editor isn’t the best choice.

This is a great area editor when it works. It systematically moves through each post within the delineated polygon and snaps it to ground. Beware! Save your edits prior to using this editor, because you cannot undo your edits – sometimes spikes are introduced! Only use this for small area edits. ITE will crash if you draw a polygon that is too large.

Geomorphic Editing – Use this editing feature to adjust the elevation for a group of posts along ridgelines, within depressions, and along slopes. It also works within crater walls and along the crater rim. With this editor, you are essentially drawing a line along the face of a feature with the goal of changing the elevation of posts within a defined (interpolation) distance on either side of the line.

Press the icon indicated below from the ITE Toolbar:

The most commonly used Algorithm with this editor is “Uniform Slope”. Set the “Interpolation Distance” by first estimating the distance based on the resolution of the DTM to be edited (For HiRISE DTMs use 1 – 5 M, MER MI DTMs require a much smaller distance). Then, using trial-and-error, find the best distance for the type of feature that you are editing. Generally, along the sides of slopes, a greater Interpolation Distance works well, while along a crest or ridge line, a narrower, or smaller distance is used. Be sure to toggle between Limited/Off for the graphics display to make sure that the posts (as displayed by contours) are on the ground.

UNDO The button indicated below allows one “undo” following the execution of any edit except the “Snap_to_ground” area edit. Use this if any edit function produces unexpected and undesired results! But remember that you can only “back-up” once.

Editing Using a Triangulated Irregular Network (TIN) A special editing function is accessed by clicking on the indicated icon. This edit feature allows the user to use TIN tools to edit a delineated area within a DTM/GRID. Remember that the DTMs normally produced for editing are in a GRID format, meaning that the posts are in a regularly spaced grid pattern. A TIN is an irregularly spaced framework of posts. Unique editing tools are available once a defined area is temporarily converted into a TIN. Use this edit feature for terrain that is complicated and requires high DTM accuracy.

TIN editing mouse button functions to remember: Toggle cursor and delineate a polygon (left mouse button). Accept polygon (right mouse button) to start the area tool. Pick/Move Post = Left mouse button Delete Post = Middle mouse button New Post = Right mouse button

The first step is to click the highlighted icon. The following window will open. Draw a polygon around an area to be edited, as requested.

Once the delineated area has been converted into a TIN, the other edit functions describe above are available for use. Post editing is especially useful here. One option is to set the DTM graphic preferences to a mesh to see the posts and TIN structure easily. TIN based editing functions are flexible and powerful.

##FAQ

1. What should I do when it appears that the edit function I have selected isn’t doing anything?

   First make sure that you closed the edit polygon (area edits) or completed your line drawn (geomorphic editor). Then make sure that the edit settings are reasonable for the DTM you are currently working on. Is the Interpolation Distance defined in the geomorphic editing window entered correctly? If everything appears to be set up correctly, close the editor and re-open it. Sometimes ITE gets “stuck” and needs to be restarted.

2. I can’t get ITE to open. The Menu button for ITE is grayed out and nothing happens when I click it.

   Make sure that you have opened Load Images. From the Load Images window, correctly select both images, and press “Load”. ITE can’t be initialized without images loaded in View 1.