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9 Working with
Raster
Selection
129
Standard Selection Styles
All
The
All
option selects an entire raster image.
To select an entire raster image
Click the button on the
Raster Select
toolbar or enter
all
to the
rSelect
command
prompt.
Þ
The
All
selection option causes deselecting on the current image.
Window
Selects all raster data within a rectangular area, specified by two opposite corners.
To select raster data inside a rectangular area
1. Click the button on the
Raster Select
toolbar or enter
w
(for
Window
) to the
rSelect
command prompt.
Draw a selection window.
2. Specify two points — the opposite corners of a rectangular window.
Polygon
Using this method you can select raster with a polygonal window. All the data inside
the polygon boundary is selected.
To select raster data inside a polygonal area
1. Click the button on the
Raster Select
toolbar or enter
p
(for
Polygon
) at any
rSelect
command prompt.
2. Specify the points, defining a polygonal area boundary, entirely enclosing the
raster data to be selected.
3. Press ENTER to complete selection.
Options of Object Raster Selection Methods
Object raster selection methods
(or
object
methods) enable you to select raster
data by tools similar to those that are used in vector selection methods. For
example, the
Within Window
style selects raster data that is entirely inside the
selection window. Raster objects crossing the window boundary are not selected.
The program implements the following options of
object raster selection methods
:
Style
Picking procedure
Raster data selected
rSelect option
Object
Pick an object
Raster object
Object
Within
Window
Draw a selection
window
Inside the window
excluding
raster objects
crossed by its boundary
WWindow