Adding Points, Lines and Areas

There are many ways of adding points, lines and areas to drawings in Manifold. This topic explains how to draw these objects free hand using the Tools toolbar for drawings.

To draw new objects begin by clicking on the map layer tab in which the areas are to be created to make it the active layer. New objects are created in the active layer. It is a good idea to create new objects in a new, blank layer so that they may be easily moved up and down in the layer stack. New objects will be created using whatever formatting is specified for that drawing or map layer.

To add points to a drawing:

1. Click the Insert Point button $images\btn_shp_point.gif$

2. Click anywhere you wish a point to be created. Points will be created in the active layer/drawing.

3. When finished inserting new points, click out the Insert Point button.

4. If desired, use the Formatting Toolbar to change the formatting of the points.

Very handy: When adding points to a drawing we will often use Instant Data to also add values to a data field.

To add lines to a drawing:

1. Click the Insert Line button $images\btn_shp_line.gif$

2. Click anywhere you wish the line to begin. Lines will be created in the active layer/drawing.

3. Continue clicking to grow the line with each click to that next position.

4. Right click to finish the line. The line will end at the last left-click position.

5. Click anywhere to begin a new line, and repeat steps 4 and 5 to make another line.

6. When finished inserting new lines, click out the Insert Line button.

7. If desired, use the Formatting Toolbar to change the formatting of the lines.

To add areas to a drawing:

1. Click the Insert Area button $images\btn_shp_area.gif$

2. Click anywhere you wish the area to begin. Areas will be created in the active layer/drawing.

3. Continue clicking to grow the area with each click to that next position. The area will always grow so that the preview outline of the area is a closed figure.

4. Right click to finish the area. The area will end at the last left-click position.

5. Click anywhere to begin a new area, and repeat steps 4 and 5 to make another area.

6. When finished inserting new areas, click out the Insert Area button.

7. If desired, use the Formatting Toolbar to change the formatting of the areas.

Example: Add an Area

Click on the beginning position of the area and then click at the first position where it is to change shape. Keep clicking about the periphery of the area. As we move the mouse the boundary preview figure will "rubber band" to the current mouse position from the starting point. The rubber band is a preview of what the area will look like if the last left click is made at the current mouse position.

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At the end of the desired figure, we would click once to mark the last position and then right click the mouse to create the area.

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The area will be drawn within the figure.

Creating Complex Areas

We may wish to create areas that contain "holes" or which consist of several non-contiguous pieces ("islands"). Such areas are called branched or complex areas. To create such areas in Manifold, use a CTRL-click between several sequences of boundary line clicks. Suppose in the example above we wished to create a pentagonal area that contained a pentagonal hole:

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At the end of clicking our way around the outer periphery, instead of right clicking we would CTRL-click. We would then click once at a new starting point and click to the first position to change direction. Just as before, as we click our way around the periphery of the "hole" the boundary preview line will "rubber band" from the starting position to the current mouse position.

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At the last position we would click once to mark the last position and then right click to end the figure.

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Manifold knows that after the CTRL click we have drawn a figure within a figure, so it knows this is to be a hole and creates the complex area accordingly. Had we drawn the second figure outside the first figure, it would have been drawn as an "island." In fact, we can draw complex overlapping figures by CTRL clicking between them to create new areas of great topological complexity. Note: to keep things reasonably obvious it is usually best to create complex areas with holes or islands but not with complex internal overlaps.

CTRL click also works during the creation of lines. In such cases, a group of what appear to be separate lines will all be created as a single line object. This capability should only be used by experts (and sparingly, at that) since it quite easily leads to confusion.

Insert Line Sequence

Curved lines in Manifold are really polylines: what appears to be a curve is really one line object that is a sequence of straight portions between coordinates drawn in a "connect the coordinates" fashion.

$images\btn_shp_lineseq.gif$ At times we wish to create a sequence of straight line segments where each straight segment is a separate line object. Insert Line Sequence does this. It works just like Insert Line, except that it creates a new line object between each click.

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Creating a line using Insert Line with a few clicks and a right click will result in a single line object.

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Using Insert Line Sequence with the same clicks and a right click will result in three line objects (the middle of which has been moved to a new layer and colored orange to show it is a different object from the other two straight segments).

Creating Straight Lines between Points

Either Insert Line or Insert Line Sequence may be used to rapidly create a series of straight lines between points.

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Suppose we need to create a series of straight lines between the points above. Begin by setting Snap to Points so that the mouse cursor will snap to the nearest point.

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Make each line by clicking on the first point, clicking on the second point and then right clicking. The resultant "Click, click, right-click" pattern is very fast.

Status Bar Reports

When moving the mouse in creating a vector shape the status bar reports the length and angular bearing of the current segment as well as the location of the mouse cursor. Pressing CTRL will convert the report to use of alternate units (English or Metric) and will also enable use of ellipsoidal trigonometric calculations for the report.

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For example, when creating a line as seen above...

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...the status bar will report the mouse cursor location followed by L: length and A: angular bearing. The mouse cursor is located 75.1393 meters from the beginning of the segment at an angle of 43.88 degrees. The mouse cursor is also located at the latitude and longitude indicated.

Notes

Using Snap is a great way to guarantee positional accuracy when creating objects free hand.

By default, the Tools - Options parameter Automatically Set Insert Mode is checked ON. Automatically Set Insert Mode will automatically switch shape modes whenever an insert shape tool button is pressed to that the shape mode that is typically used with that tool. For example, when Automatically Set Insert Mode is ON, pressing Insert Line will automatically push in the Create Lines mode button and push out the Create Areas and Create Points buttons. This default choice may be overridden by choosing whatever combination of shape modes is desired after choosing the tool.

In another example, when Automatically Set Insert Mode is checked ON the Insert Areas and Insert Box, Circle, and Ellipse commands will create areas only. To create lines and points as well simply push IN the Create Lines or Create Points buttons after choosing these commands.