Polygon

Applicability:

Ribbon Group:

Create-Simple

Conditions for use:

Associated commands:

Description:

 Polygon constructs Polygon items, with options for tracing, route-finding and orthogonal graphics.

When you select Polygon the Polygon dialog is displayed:

The Polygon dialog remains displayed while the command is in force, this allows you to change Polygon parameters at any time, even while drawing a Polygon item.

The properties and their values in the Polygon dialog are as follows:

Area

This is an information field showing the dynamic area of the polygon item being drawn, reported in the current units.

Construction mode

Construction mode will affect how snapped or typed positions are interpreted, and also the offset from those positions from which to create the Polygon. You can freely switch between these modes during Polygon item construction.

Simple

You may enter the start position of the Polygon item by snapping to a position on the screen, or typing a coordinate. The corner of the Polygon item will now be locked to that point and can be sized by dragging and snapping to positions on the screen, or typing coordinates. Press Enter or double-click to complete the action.

If you make a mistake and need to remove a point, press the Backspace key. This removes the last point input, each subsequent press of the Backspace key will backtrack through the previous points.

Trace

This mode constructs a Polygon item by tracing over existing graphics. This overcomes many of the frustrations normally encountered when tracing over existing graphics. Used in conjunction with the ability to pan and zoom over the map in mid-command, and the facility for having more than one view of the map displayed, tracing over base data can become a simple and reliable task.

Snap or type a position for the start of the trace. This starts the trace anywhere on the map, but as you are tracing, you may want to choose a vertex on the geometry to be traced.

Snap a position to trace to. Clicking the mouse when the cursor is over existing geometry will cause SIS to search for a continuous path between the first and second point. The trace will follow exactly over the path of the geometry being traced, irrespective of how many intermediate vertices it contains.

The trace sequence is drawn on screen using a thick outline. You can press the Backspace key to return to the previous trace point, or Shift+Backspace to step back over the vertices of the last intermediate trace sequence.

The trace path will not jump between different bits of geometry. However, if you trace to the intersection between two pieces of geometry, or where two geometry ends meet, then the trace will be able to jump across the intersection.

To trace over an existing geometry completely, click the first point, then hold the Ctrl key down, and click anywhere along the geometry to be traced, near to the first point in the direction you wish to trace. SIS will not insert a vertex at this point, but will attempt to trace the geometry right to its end, no matter how long this is, or how many intermediate vertices are needed.

If you do not wish to follow existing geometry, you can enter a position while holding the Shift key to jump directly to the position you input, which need not be on existing geometry.

In addition, if the start and end positions of a trace segment are on topological Link items, SIS will automatically perform a topological route-find using a shortest-route
algorithm.

Press the Enter key to accept the trace sequence, or press Ctrl+Enter to close the shape, joining the last point back to the first. A Polygon item will be created along the traced path.

Find route

SIS will look for a route between the positions you enter. The route can be made up of geometry from any item. If your positions are far apart, then SIS may spend some time looking for a route.

Orthoganol

All of the Polygon item segments will be corrected to be parallel to the X and Y-axes, giving right-angled corners. If you wish to draw Polygon items at angles other than 0, 90, 180 and 270 degrees, you must first change the orientation of the axes Rotate (View-Axes).

Right angles

Each Polygon item segment will be created at right-angles to the previous segment.

Offset

Before the final Polygon item is created, SIS can offset it from your entered positions. Entering an offset will result in the new Polygon item being offset by the specified distance, positive values resulting in an offset to the left of the entered positions and negative values to the right of the entered positions. To draw several Polygon items at once which trace existing graphics, you can enter several space separated offset values, for example:

100m 200m 500m 2000m

or use REP, R or r for repeated offsets, for example:

100m REP 4 - this would give 4 offsets spaced at 100m

Perimeter

This is an information field showing the dynamic perimeter of the polygon item being drawn, reported as an integer in the current units.

Z Height

You can enter a value here to override the height of each snap with a fixed value.
 
Refer to Constructing Polygon items and Editing Polygon items.

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