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SurView Tutorial

Zoom/Pan

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Zoom/pan all copies of SurView

zoom/pan all SurView menu item

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.


Zoom/pan using the keyboard

The arrow keys & numeric keypad keys can be used to zoom/pan on the map:

Insert
Zoom in
Home
Pan NW
Page Up
Pan NE
Delete
Zoom out
End
Pan SW
Page Down
Pan SE
Num Lock / * -
7/Home
Pan NW
8
Pan up
9/Pg Up
Pan NE
+
4
Pan left
5
Overview
6
Pan right
1/End
Pan SW
2
Pan down
3/Pg Dn
Pan SE
Enter
0/Ins Del
Arrow
keypad
Pan up
Pan left Pan down Pan right

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.


Zoom/pan cursor

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

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
pan cursor
Pan Cursor
Clicking the LEFT mouse button or pressing numeric keypad '5' anytime will toggle between zoom & pan modes. The 'pan' cursor is identifiable by the cross-hair in the centre.

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
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
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.


Zoom/pan by numbers

zoom by numbers

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
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.


Undo last zoom/pan

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.


Previous map views

previous map views

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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