VATT -- Image Attribute Exploration

Prints a continuous report of attribute and other information pertaining to a pixel position on a database file, pointed to by the display cursor. The following is continuously updated on the terminal, as the cursor is moved: absolute database position, georeferenced position, grey-level value, and attribute data.

PARAMETERS

VATT is controlled by the following global parameters: 

Name     Prompt                                  Count     Type
FILE     Database File Name                      1-64      Char
DBGEO    Database Georeference Segment           0-1       Int
DBIW     Database Input Window                   0-4       Int
DBIC     Database Input Channel List             1-16      Int
TEXSEG   Database Text Segment                   0-16      Int
TFILE    Output Text File Name                   0-64      Char

FILE

Specifies the name of the PCIDSK image file to be interactively explored. 

 EASI>FILE="filespec"

DBGEO

Specifies the georeference segment associated with the image. 

 EASI>DBGEO=2

DBIW

Specifies the window of data from the database which is currently filling the entire display. 

 EASI>DBIW=Xoffset,Yoffset,Xsize,Ysize
 EASI>DBIW=                     | overview of entire database
                                | is displayed

DBIC

Specifies the image channels on the database that will be read each time the cursor is moved. 

 EASI>DBIC=i,j,...

TEXSEG

Optionally specifies the database segment (type 140:TEX) that holds the attribute data that should be used in conjunction with the image channels. 

 EASI>TEXSEG=k,l,...

TFILE

Optionally specifies a text file to save all geocoded points selected by the mouse. If more than 1 channel is selected in DBIC, only the value of the first channel will be saved. 

 EASI> TFILE="filespec"
The format of the file is X, Y, and Z where Z is grey level value of the channel.

DETAILS

VATT interactively explores an image using an image on the video display as a background. VATT tracks the position of the display cursor and interactively updates the following for each position the cursor is moved to: database absolute position, georeferenced database position, grey-level values, and attribute data.

Note: The georeferenced position is not printed if the database file is NOT georeferenced to a coordinate (projection) system. For example, if the image is specified in METREs, the ground distance in metres will be printed instead of easting/northing and longitude/latitude.

A georeference segment (DBGEO) with defined image bounds (e.g. the master georeferencing segment) is required to calculate the easting/northing and the longitude/latitude of the cursor position. (A zone number is required for UTM and State Plane projections.) If, for any reason, VATT cannot calculate the longitude/latitude of the cursor position, the entries are left blank.

VATT does not transfer the image to the display. This must be done before running this program, using IVI. DBIW specifies the window of data from the database which is currently on the entire display. If DBIW is unspecified, it is assumed that an overview of the entire database is on the display.

A text segment (TEXSEG) containing attribute data may be used in conjunction with each specified image channel (DBIC). A text segment must contain attribute data which follows the format described in the `Using PCI Software' manual, Attribute Data chapter. If a text segment is not specified for a particular channel, the channel descriptor is printed instead of the attribute data.

TFILE allows the user to save all geocoded points selected by the mouse. This is useful for the user who wants to extract geocoded points with grey level value from an image channel.

EXAMPLE

The following example shows how to interactively determine the land use at various positions on the training data set file.

Transfer an overview of first three TM bands of image to the display, and enhance it. 

 EASI>FILE="irvine.pix"
 EASI>DBIC=3,2,1
 EASI>VDOC=1,2,3
 EASI>DBIW=             
 EASI>VDOW=
 EASI>RUN IVI
 EASI>RUN DCP "ID 3,2,1:LE"
Explore pixel attributes. Specify the land use channel (6) and the three TM channels (1,2,3) as input channels, and specify text segment 19 to contain attribute data for image channel 6. Text segments are not specified for image channels 1, 2, and 3. 

 EASI>DBGEO=1
 EASI>DBIC=6,3,2,1
 EASI>DBIW=
 EASI>TEXSEG=19
 EASI>TFILE=
 EASI>RUN VATT
Suppose that the cursor is at display position (200X, 200Y). The following report will appear on the user's terminal. The report changes as the cursor is moved.

VATT Image Attribute Exploration V5.3 EASI/PACE

Pixel Coordinate ( 200 :X 200 :Y ) Longitude/Latitude ( 117d42'16.30" W :Lon 33d41'43.52" N :Lat) Easting/Northing ( 434705.00 :E 3728415.00 :N )

Channel Greylevel Attribute 

   6            75       Barren       Mines/Quarries/Pits
   3            36      0.63 - 0.69 micrometres: Red
   2            30      0.52 - 0.60 micrometres: Green
   1            70      0.45 - 0.52 micrometres: Blue-Green
Move display cursor for update, Press <x> key to exit:

About PCI Help Gateway