AGGREG -- Interactive Class Aggregation

Merges up to 255 selected classes together. Using the clustering results, the user can display classes in different colours, group classes into aggregates, change the colours of classes, and change classes under graphic bitmaps to another class.

See Also: KCLUS, ISOCLUS, NGCLUS, NGCLUS2, MLC, PCTMAKE, SIEVE

PARAMETERS

AGGREG is controlled by the following global parameters:

Name     Prompt                                  Count     Type
FILE     Database File Name                      1-64      Char
DBIC     Database Input Channel                  1-1       Int
VDOC     Video Output Channel                    1-1       Int
DBIW     Database Input Window                   0-4       Int
DBWC     Database Work Channel                   1-1       Int
DBOC     Database Output Channel                 0-1       Int
DBPCT    Database Pseudocolour Segment           0-1       Int

FILE

Specifies the name of the PCIDSK image file.

 EASI>FILE="filespec"

DBIC

Specifies the input channel from the clustering results. This channel should be the output channel from one of the following programs: KCLUS, ISOCLUS, NGCLUS, NGCLUS2, or MLC.

 EASI>DBIC=i

VDOC

Specifies the video output channel

 EASI>VDOC=i

DBIW

Specifies the window of data from the database which is currently loaded into the display.

 EASI>DBIW=Xoffset,Yoffset,Xsize,Ysize

If unspecified, it is assumed that an overview of the entire database is displayed on the display. DBIW will also be used as the output window.

DBWC

Specifies a working channel for the program. This channel is needed in order to avoid overwriting the input channel. DBWC can be equal to DBOC to save disk space.

 EASI>DBWC=i

DBOC

Optionally specifies the output channel to store the aggregation results.

 EASI>DBOC=i
 EASI>DBOC=     | no output channel

DBPCT

Specifies the pseudo-colour table segment to be used. The default is a random colour pseudo-colour table.

 EASI>DBPCT=i
 EASI>DBPCT=            | defaults to random colour PC table

DETAILS

This program belongs to the classification package. The diagram in the manual overview shows that AGGREG is used after actual classification. A limit of 255 classes can be used in this program. Classes with the value greater than 255 will be neglected.

AGGREG is an interactive program which allows the user to perform different tasks upon the clustering results. The tasks are as follows:

to display all classified classes in different colours
to display user selected classes
to roll and display each class
to roll and display each aggregate
to change colours of different classes or aggregates
to change class of an area under a graphic bitmap to another class
to group different classes into different aggregates
to add classes to an existing aggregate
to save results into an output channel
to review a list of aggregate entries for comparison

When the user loads the program, a main menu will show up on the screen as follows:

 1 : Select/Reset pseudo-colour table
 2 : Enlarge/Reset Image
 3 : Change class colour/Change class/Exploration
 4 : Aggregation
 5 : Review aggregate results
 6 : Save current pseudo-colour table
 7 : Save aggregate results to output channel
 8 : Save aggregate table to report
 9 : Reset and restart program again
 x : EXIT program


 1 : Select/Reset pseudo-colour table

Inside this option, the user is allowed to choose different pseudo colour tables.

 2 : Enlarge/Reset Image

This is for the case where the user has a very large image, for example, a 3K X 3K image. This option allows the user to load a certain area of an image from the database while running the AGGREG program.

 3 : Change class colour/Change class/Exploration

This option allows the user to explore the classified image by using a pointing device (i.e. mouse or trackball) or keyboard. In addition, the user can change the colour of a class, or change the class of an area under a graphic bitmap. The changes must be made under video graphics plane 1 only in order to be recognized. The area of a polygon can also be found in this option.

 4 : Aggregation

This option allows the user to aggregate classes together by using a pointing device (i.e. mouse or trackball) or keyboard.

 5 : Review aggregate results

This option allows the user to review the aggregate results in the form of a table.

 6 : Save current pseudo-colour table

This option allows the user to save the current pseudo-colour table, as shown on the image, to a PCIDSK segment.

 7 : Save aggregate results to output channel

This option allows the user to save the current aggregated results to an output channel. Thus, the user can continue the aggregation using the output channel as input for the AGGREG program.

 8 : Save aggregate table to report

This option allows the user to save the aggregate table to a text file in PCI attribute format. After the execution of this program, the user can run TEXREAD program to read the file and create a new attribute segment.

 9 : Reset and restart program again

This option allows the user to reset the program without exiting the program

 x : EXIT program

This will exit the program. However, if the user has not saved the results, a warning message will be given.

There are a number of points which should be noted when using this program:

Classes are results obtained from the clustering program. An aggregate is a grouping of one or more classes.

During creation of new aggregate, the user may select different classes to aggregate together. The colour of the first class selected will be the colour of the new aggregate.

During aggregation, the user may want to see certain classes only, with the remaining classes in a background colour (Default is black). This can be achieved by choosing the option "(3) Display individual classes/aggregates" inside the AGGREGATION menu. To reset the colour for every class/aggregate, choose the option "(1) Display all classes" inside the AGGREGATION menu.

Before running this program, the user should first create/ initialize an output display. AGGREG will load the image to the display automatically.

The user may want to first eliminate clusters with number of pixels smaller than a certain threshold before running this program, this can be achieved by running the program SIEVE. See SIEVE for more details.

If true colour is desired instead of random colour, the user can run the PCTMAKE program to create an almost true colour pseudo-colour table. See PCTMAKE for more details.

In the option to change SEVERAL classes to one class under graphic, the user can enter a range by using negative number to represent the last value. For example, "1,-10,12,20,-30" represents classes 1 to 10, class 12, and classes 20 to 30.

EXAMPLE

One of the unsupervised classification programs was run on the file irvine.pix and the results were output to channel 7. The user now wishes to aggregate the classes into larger, more meaningful aggregates.

 EASI>FILE="irvine.pix"
 EASI>DBIC=7  
 EASI>VDOC=1
 EASI>DBIW=
 EASI>DBWC=8
 EASI>DBOC=9
 EASI>DBPCT=
 EASI>RUN AGGREG

About PCI Help Gateway