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KeyMap

Introduction

Using KeyMaps

Creating a KeyMap

Creating a KeyMap view

Padding

Changing the appearance of a KeyMap

Properties

Introduction

A KeyMap is a special kind of Polygon item that draws a named Item as a backdrop, with an optional named View, plus filled polygons for associated Map Frame items. This is useful for placing KeyMaps on Print Template objects.

KeyMaps are identical to backdrops, and are stored as items in a NOL in just the same way.

KeyMaps are stored in special library folders known as star folders along with North Points and Scale Bars. Any main folder names which are prefixed with a 'star' (asterisk) are normally hidden from view. If you cannot see the *KM folder right-click on the top Libraries node of the tree and select Toggle ‘*’ Objects. This will make all hidden folders and objects visible in the library tree. Selecting this option again will hide them from the tree.

Using KeyMaps

KeyMaps may be added to Print Templates in three ways:

Select the Add KeyMap option in the Print Wizard Options dialog:
Right-click on a Map Frame item on a Print Template and select Create KeyMap…
Store a Print Template which has a KeyMap already placed on it.

Whether you place a KeyMap using Print Template [File-Print Template] or Quick Print Template [File-Print Template], or afterwards on a composed Print Template, the process is the same: select the KeyMap from the displayed list, then 'click-drag-click' a rectangular area on the template preview or composed template where you want the KeyMap to appear.

Creating a KeyMap

In the Libraries Control Bar, use Toggle '*' Objects to display the *KM folder within Item in the standard library, copy the entire *KM folder and paste it into the (temporary) library.

UK 50km and UK 100km are already present in the *KM folder. If you wish to add another item paste the new item into the *KM folder in the (temporary) library. The backdrop will now be listed as a KeyMap when you use Print Template [File-Print Template] or Quick Print Template [File-Print Template] or use KeyMap [Paper-Annotate] on a Map Frame item in a Print Template.

Example of creating and using a KeyMap:

Create or load a user NOL and make it current:
Select the item or items to be used as the KeyMap. For example if you have a simple layout of your area of interest you could select that. This example shows a polygon for the boundary, a blue line for a river and a black line for a major road. There are two points for populated areas; "BIG TOWN" and "Other place":
Select all the items and store then in the NOL, Store Item [Create-Miscellaneous].

You must use *KM for the Folder entry, this makes the stored item a KeyMap.
It is a good idea to store the view, Store View [Views-Map Views], as this can be used in conjunction with the KeyMap later:

Unlike the KeyMap the stored view can be saved anywhere. Stored views can be recalled to help navigation in the map. For example if you create a view around the “BIG TOWN”, and you then go to “Other Place” in the map and then wanted to go to “BIG TOWN” you could recall that stored view in any SWD and the map window would relocate to that view.
Save the NOL, the KeyMap is now ready to use.
To use the KeyMap go to the Print Wizard Options dialog page of the Print Wizard and select Add KeyMap:
On completion the end result would be something similar to the following, but the KeyMap may not look as you would like to:
This is where the Stored View can be used. Select the KeyMap and click the right button, select Properties... and set the view in the All tab of the Properties of KeyMap dialog:
You will now see a view like the following. There are many styling options you can use on the Keymap to set the hatch or the pen. You can also add and store the KeyMap on a print template so you do not have to add it in the Print Wizard.

Creating a KeyMap view

Add your backdrop as a Backdrop Overlay, and zoom to its full extent.
Use Store Item [Create-Miscellaneous] to store this extent. Give the stored view a name which is memorable, preferably the same name as the KeyMap for which it will be used.

If you want padding around the KeyMap, simply zoom out slightly before storing the view.

See the Example of creating and using a KeyMap above.

Padding

The first thing you will notice when you have placed a KeyMap is that it appears as a crosshatched rectangle with a smaller crosshatched rectangle within it. This is because the KeyMap displays the extent of the Map Frame item (the hatched area) with a default padding factor of 2.

In this example Surrey Heath district is much larger than 2 times the displayed map.

The padding factor can be changed by selecting the KeyMap and changing the value in the Properties Control Bar, as shown:

Changing the padding factor to 40 makes the KeyMap display an area of Surrey Heath 40 times larger than the map area:

Notice that the hatched map area is still central in the KeyMap, so not all of the Surrey Heath area is displayed. In this example it is necessary to increase the padding factor to 85 before the whole of Surrey Heath is visible. This also has the possibly undesirable effect of displaying the hatched map area centrally, with the Surrey Heath area off centre:

In these circumstances it is recommended to ignore the padding factor and instead set the Keymap View. A KeyMap View is a named view stored in a NOL which defines the map extents of the KeyMap item.

All of the KeyMaps contained in the Backdrops and KeyMaps NOL have a corresponding named view for this purpose.

The Keymap View can be set in the Properties Control Bar by copying the KeyMap Backdrop name, excluding the *KM. prefix, into the Keymap view property value as shown below:

This setting overrides the padding factor and ensures that the whole of Surrey Heath is displayed in the KeyMap as shown:

Note: All of the KeyMap views provided in the Backdrops and KeyMap library have a 5% padding factor around the backdrop graphics so the bounding rectangle does not touch the graphics.

Changing the appearance of a KeyMap

The KeyMap rectangle is simply a special class of Polygon item, so its Pen and Brush can be changed in the same way as other Polygons. By default the Pen is 'by overlay' and the Brush is opaque white.

The colour and appearance of the Surrey Heath area is determined by the appearance of the item stored in the *KM library folder.

The hatched map area appearance can be changed in the Properties Control Bar with the Brush for outlines and Pen for outlines properties. Note that you can only set brushes or pens which are stored in a NOL, or enter an implicit string which specifies the brush or pen style:

The following is an example of a circular KeyMap, where the surrounding thickened blue circle does not touch the backdrop item.

This can be achieved either by storing a named view slightly larger than the backdrop item and using that as the KeyMap View or by creating a pen which is offset by 2mm and drawing the circle over the KeyMap rectangle. With both the circle and the KeyMap selected, use Union [Analysis-Boolean Operations] to add the circle to the KeyMap.

Item Properties

Properties

Polygon: _area#
The Polygon covered by the item in square metres.
Brush for outlines: _brushOutline$
The Brush with which to fill associated Map Frame item polygons in the Key Map.
Clockwise: _bClockwise&
Is the item geometry defined in a clockwise direction?
KeyMap backdrop: _keyMapBackdrop$
The named Item to draw as the Key Map backdrop.
KeyMap view: _keyMapView$
The named View to draw the Key Map backdrop within. If this is "" then the Key Map will draw around its associated Map Frame items, padded by the value of Padding factor.
Number of edges: _numedges&
The number of edges in a geometrical shape.
Number of loops: _numloops&
The number of loops used by a Polygon item. Most Polygon items have only one loop. However, any holes or islands will be stored as extra loops.
Number of photos: _nPhoto&
The number of associated Map Frame items in a Key Map.
Padding factor: _padFactor#
The padding factor to apply to the accumulated extents of the associated Map Frame items when drawing a Key Map with no named View.
Pen for outlines: _penOutline$
The Pen with which to draw associated Map Frame item polygons in the Key Map.
Photos: _photos$
A space-separated list of the item IDs of the Map Frame items associated with a Key Map.
Splinter factor: _splinter#
The splinter factor of the Polygon. A circle has a splinter factor of 1. A very long and thin area could have a splinter factor of 100. Polygon items with large splinter factors are often produced by overlapping LineString items which are almost but not quite the same.

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