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OZGIS50.TUT
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1992-01-04
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MAP REGIONS
===========
Geographic files can be displayed in user-defined parts of the
monitor.
A map region is established when a geographic file is displayed. The
region is defined by the geographic window (or subset) and its displayed
defined in a map.
A geographic window is the total area of the geographic file. Files
are subset as a data preparation process.
A viewport is selected by positioning the cursor on the monitor with
the mouse or arrows (i.e. it is a rectangular part of the screen).
Map regions enable complex map layouts to be generated. Maps often
have only one region, typically zones from one geographic file displayed on
the default viewpoint on the monitor. Multiple regions, each with defined
window and viewport provide many possibilities e.g. subsets of a main map
can be added as new regions at high magnification e.g. extreme parts of a
map can be chopped off and added on as new regions in a corner e.g. several
files for different parts of a country could be displayed as separate map
regions.
It is possible to overlay data from geographic files onto a map
region. More than one set of zones from a geographic file can be displayed
in a region but the zones being displayed will overwrite any underlying
zones.
Geographic files are automatically windowed, scaled and clipped for
display on map regions.
When multiple files are displayed on a region, the precedure order is
quantised zones, lines, sites, line overlays, markers and finally text at
points.
Multiple regions can be defined anywhere on the map display area of
the monitor. However, if regions overlap the display procedure is
established by the order of display. Therefore the user should consider
the order of display carefully in multiple region presentations.
Geographic files can be displayed in any order, and
regions can be defined and changed as desired. Many of these operations
destroy the data in the display system memory (the map display is
corrupted) so F3 must be typed to completely regenerate the map display.