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:
- DCW - Digital Chart of the World
- DLG - Digital Line Graph
- WDB - World Data Bank II
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
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:
- Hypsography
- Hypsography-Sup
- Physiography
- Political/Oceans
- Roads
- Railroads
- Transportation
- Utilities
- 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:
- North America
- Europe/Northern Asia
- South America/Africa
- South Asia/Australia
- 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.
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.
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:
- AFRICA
- AMERICA
- ASIA
- EUROPE/ASIA
- EUROPE
- NORTH AMERICA
- SOUTH AMERICA
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.