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SurView TutorialZoom/Pan |
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This option allows all zoom/pan operations (described below) to be applied to all copies of SurView, so that one copy of SurView can control the view of the other copies.
This is particularly useful when viewing grid images. Several copies of
SurView can be running at the same time, since it uses very little memory.
Open each image in a separate copy of SurView. Then resize the windows so
that all images can be seen. Now designate one copy as the controller by
enabling the View | Zoom/pan all copies of SurView. All zoom/pan
operations on that copy will be transmitted to the other copies and they
will all zoom/pan together.
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The arrow keys & numeric keypad keys can be used to zoom/pan on the map:
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Arrow keys & numeric keypad 1-9
These keys have no effect in the stacked profile window. In the map
window, they are used to pan left, right, up & down (and diagonal for
the numeric keypad). The amount of pan is half a screen height/width, but
can be doubled by using the Shift key in combination with the arrow keys.
The Overview key will zoom/pan in a single keystroke to show the entire map 'overview' - the bounding box of all of the files in the current File Display List.
If the zoom/pan interactive cursor has been activated with Edit | Zoom/Pan, for either the map or stacked profile window, the arrow & numeric keypad keys are used in a similar, but slightly different fashion, to manipulate the zoom/pan cursor.
The state of the NumLock button is irrelevant - the keys work in either mode.
Insert/Delete keys
The Insert key is used to zoom in 2X and the Delete key is used to zoom out 2X.
The Shift key doubles the amount of zoom. Note that the remaining 4 keys
(Home, End, PageUp, PageDown) on the Insert/Delete keypad are identical to
numeric keypad keys 7, 1, 9 & 3 and therefore they are used for panning
operations.
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SurView features a unique and special zoom/pan cursor that provides several advantages over traditional drag-select-release zoom cursors:
Activate the zoom/pan cursor with View | Zoom/pan or just press ctrl-Z.
![]() zoom cursor |
Zoom cursor
The initial mode is as a 'zoom' cursor, identifiable by the partial
frame in the centre. The outer frame is the selection area.
![]() pan cursor |
Controlling the cursor
In zoom mode, left and/or downward motion of the mouse will make the
selection area smaller. Moving the mouse right and/or up will make the
selection area larger. Left/right motion seems to be the most intuitive.
You can also use the arrow keys and numeric keypad keys to resize the
zoom area:
In pan mode, mouse motion in any direction moves the cursor in the indicated direction. You can also use the arrow keys and numeric keypad keys to move the mouse in any direction. The 1,3,7,9 keys on the numeric keypad move it in diagonal directions.
The Space key toggles the keyboard motion between 'slow' and 'fast'.
Exiting the zoom/pan cursor
Keystroke | Action |
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ENTER or RIGHT mouse button |
select the area, exit and redraw the map |
Esc or Q or Del or Delete |
cancel zoom/pan and return to normal mode |
Colours & styles
The cursor is drawn so that it should be visible against most backgrounds
(except grey). To increase visibility, it may be necessary to change the line
style, thickness or colour using the following keys:
Keystroke | Action |
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L | cycle through available line styles |
C | cycle through a list of primary colours |
T | Increase line thickness (up to a certain point, after which the default thickness is restored). Note that this only applies to solid lines - it has no effect on dashed or dotted lines |
Help
During the operation of the zoom/pan cursor, the caption of SurView's
window will flash the message:
H=help, LEFT BUTTON=toggle zoom/pan, RIGHT BUTTON=select, ESC=quit |
Pressing H will bring up a short summary of the keystrokes.
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In addition to the zoom/pan keystrokes and interactive zoom/pan cursor, there is a third method of zooming/panning, using the View | Zoom/pan by numbers dialog box.
The dialog box is initialized with the centre (x,y) and the width/height of
the current view.
Enable Location (Pan) if you want to pan the view. Enable View extent (Zoom) if you want to zoom. Both options can be enabled if you want to zoom & pan at the same time:
Location (Pan) | View extent (Zoom) | Result |
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enabled | disabled | the width/height of the current view is retained - only the location is changed |
disabled | enabled | the width/height is changed and the map remains centred on the same location |
enabled | enabled | the location is changed and the width/height of the view is set, relative to the new centre of the map |
Location (Pan)
To pan, choose (easting, northing) or (longitude, latitude) mode and enter the
corresponding (easting, northing) or (longitude, latitude) of the desired reference
point and indicate one of 9 parts of the map to which the point refers. For example,
if you select the centre position, then SurView will move the view so that the
specified (x,y) will be at the centre of the new view. If you select the upper
left corner of the map, then SurView will move the view so that the specified
(x,y) will be at the upper left corner of the view.
The current projection is shown below the settings. (easting,northing) values that are entered must be in that reference system. Once (easting, northing) or (longitude, latitude) settings have been entered, toggling to the co-ordinate mode will show the values in the 'other' reference system.
View extent (Zoom)
To zoom, specify either the width or height of the view. The current aspect
ratio of the window is retained: if you change the width, the height is recalculated
and vice versa. For example, if the current view is Width=1000 m, Height=500 m,
you can set Width=2000 or Height=1000 to zoom out 2X. Change the Width from 1000
to 500 and the map will zoom in 2X. Zooming operations are centred on the current
centre of the view, unless the Location (Pan) option is also enabled, in which
case you can choose the new centre of the view.
Zoom/Pan all copies
If this option is enabled, the zoom and/or pan operations will be applied to
all copies of SurView, with the exception of copies that are minimized.
Note that this option is similar to the global View | Zoom all copies of SurView option
in its operation, but the two options are independent of each other. If the option
remains unchecked in this dialog box, no other copies of SurView are zoomed/panned,
regardless of the setting of the View | Zoom all copies of SurView option.
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The current 'view' (bounding box) of the map is saved in a list each time a zoom or pan operation is performed, using either of these methods:
SurView saves the last 20 views - when the list is full, the oldest is discarded to make room for a new one. You can 'undo' the zoom/pan operations in sequence by selecting View | Undo last Zoom/Pan or just press ctrl-U
Note the difference between the ctrl-U and Delete keys. The Delete zooms out. If the previous zoom/pan operation was Insert to zoom in, then this will effectively undo the last zoom operation, but in fact, both keys are treated as zoom operations and the view preceding their use is stored in the 'undo' table, accessed by ctrl-U.
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The View | Undo last Zoom/Pan (ctrl-U) option is used to undo the LAST zoom/pan operation from the last entry in the list of 20 saved views. This list of saved views can be accessed in a direct manner by selecting the View | Previous map views option.
In this dialog box, the bounding boxes of each view are drawn as
simple outlines. The Cycle button will cycle through all of
the saved views, highlighting each one in turn and displaying the
co-ordinates of the view at the bottom of the dialog box. When the
desired view is located, press Ok and the map will be redrawn
with the selected view.
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