5.0 IMAGE TO VECTOR

IM2VECT mode supports selection of control points from a vector graphics display. In this mode, two main windows are displayed simultaneously. The image on the right is the search image, which is the image to be registered. The window on the left is the reference frame, which contains a graphics display of vectors.

Figure 5.0.1. Image to Vector Display

Vector data is displayed in the reference frame and is scaled to fit entirely in the panel. If the search image has a valid DDR, the vector data is displayed in the projection of the image. Since this is vector data, and not an image, it may be rescaled to any dimensions. The vector display may be resized to any screen dimension, and the vectors will be rescaled and redrawn to fit entirely in the panel.

Once vector data is loaded, smaller regions of the vector display may be scaled to fit the panel. To select a smaller region, move the cursor into the vector display area and press and drag the middle mouse button. A rubberbanding rectangle will outline the selected region. Once the middle mouse button is released, this subregion will be scaled to fit the vector display panel. This procedure may be repeated on this subregion if so desired. To unscale, press the rightmost mouse button in the vector panel. When selecting a subregion, it is advisable to select a roughly square area rather than a long rectangular area, so that when the subregion is scaled to fit the vector display panel, it appears more normal.

5.1 Vector

Several Vector Data Types are supported by TIEPTS. They are:

The type of vector data to use and the location of the data are selected in the Parameters panel. The default is DCW.

5.1.1 Common Parameters

Lat:, Lon:
Min:, Max:
These text fields show the minimum and maximum latitude and longitude values of the area currently being displayed in the search image window. This area is normally the entire search image. The area of interest can be changed by either changing the values in the text fields, or by using the second mouse button to select an area. This is done by moving the cursor into the search image window, then clicking the second mouse button and dragging it. A rubberbanding rectangle will outline the area. Once the second mouse button is released, the text fields are updated with the values of the selected area. The Update button is pressed so that the DCW tiles and the vectors in the reference frame are updated for the new area. Note that this does not update the vector panel.

Background

UnZoom

Cancel

5.1.2 DCW Parameters

The Digital Chart of the World is a worldwide set of information in 1:1,000,000 scale. Currently, only the vector data is supported in TIEPTS; although, point and polygon information is also provided with the DCW. A complete description of the DCW data set can be found in the 'Military Specification, Digital Chart of the World' manual, MIL-D-89009, 13 April 1992.

Feature
This menu button displays a list of available coverages for DCW. The coverages are:

Library
This menu button allows the user to select the area that the search image falls in. The DCW is delivered in a set of four Compact Disks (CD). Each of the CDs contains a single DCW library. These libraries are:

Update
This button is used to search the DCW files and update the reference frame, which contains the vector graphics. When the search image is large, or a number of Features have been selected, the time to search the files and load the graphics can be great.

Write
This button writes the information from the vector files into a LAS labeled table format, for use in other LAS programs.

5.1.3 DLG Parameters

The Digital Line Graph are ASCII format files in 1:24000, 1:100000, and 1:250000 scale. DLG data typically provides detailed line and point data. Only line data is supported in tiepts. This line data may include hydrography, roads, and railroads.

Vector File
This menu button allows the user to Load new or more vector files, or to Merge vector files. Each button provides a "File Selector" panel from which existing vector files may be selected. The program assumes that the DLG data files exist in a /dlg subdirectory. This panel will be updated in the future to allow more selection options.
Load
This button is used to load a single DLG data file into the Reference frame (all previously loaded vectors are deleted), or to load all known DLG data files into the Reference frame. The All button has been added to save time in selecting files. It loads all of the known DLG data files, and excludes the Streams and Class 4 Roads vectors.
Merge
This button is used to repetitively load DLG data files, without deleting the previously loaded vectors. This option may be used to load the Streams and Class 4 Roads vectors for specific areas after an All option has been selected.

Write
This button writes the information from the vector files into a LAS labeled table format, for use in other LAS programs. This option is currently not available for DLG data, only DCW data.

5.1.4 WDB Parameters

The World Data Bank provides a set of vectors for the entire world. Vectors are typically in 1:3,000,000 scale.

Continent
This menu button allows the user to select the area that the search image falls in. The options are:

5.2 Align

This function allows manipulation of vector positions to fit the underlying image. To select a point by alignment, zoom the region of interest and select Align. Vector data will be overlayed on the zoom image display. The following operations may be performed:

Translate
This radio button allows linework shifting in the X and Y directions using the arrow keys. Translation may be performed in either the Zoom or Full Resolution displays, one pixel per key press, relative to the window. Shifts of 10 pixels can be performed by holding the "Shift" key. Note that a single pixel shift in the full resolution window is multiplied by the zoom factor for the zoom window. Hence, it is convenient to use the full resolution window for coarse adjustments and the zoom window for subpixel accuracy.

Translation may also be performed using the mouse, independent of the radio buttons. Press the LEFT button in either the zoom or full resolution windows, and drag. The linework will shift relative to the mouse movement until the button is released.

Rotate
This radio button allows rotation of vectors about the centermost point in the zoom or full resolution windows, using the arrow keys. The RIGHT and UP arrow keys rotate linework counterclockwise. Similarly, the LEFT and DOWN keys rotate linework clockwise. Each key press rotates 1/100 radians in the given direction. Rotations of 1/10 radians may be performed by holding the "Shift" key.

Rotation may also be performed using the mouse, independent of the radio button, by pressing the MIDDLE mouse button in the zoom or full resolution windows and dragging. Dragging right or up rotates linework counterclockwise; whereas dragging left or down rotates linework clockwise.

Scale
This radio button allows stretching/shrinking of the linework using the arrow keys. Scaling/shrinking is performed relative to the X or Y directions about the centermost point. The RIGHT and UP arrow keys stretch the linework along the X and Y axis, respectively. Similarly, the LEFT and DOWN arrow keys shrink the linework along the X and Y axis, respectively.

Scaling may be performed using the mouse, independent of the radio buttons, by pressing the RIGHT mouse button in the zoom or full resolution windows and dragging. Dragging right or up stretches linework along the X and Y axis, respectively. Dragging left or down shrinks linework along the X and Y axis, respectively.

Blend
This slide bar mixes the zoom window linework into the underlying image. The value displaying above the slide bar represents the percentage of the linework dissolved into the image. Hence, if 100, the linework is invisible. Similarly, if 0, the line is totally displayed. Blend is effective at checking alignment, since the linework obstructs the view of the underlying image.

Accept
This button generates a tie point from the current alignment. The centermost vector point is determined and is tied to the underlying subpixel. The Verification panel will appear for acceptance/rejection of this point. If accepted, the point is written to the TPS files, and the vector is redisplayed with the new rough transformation computed.

Cancel
This button removes the alignment panel and vectors are redisplayed in their previous alignment.