Adding Shapes

The commands in the Tools toolbar are used to insert new points, lines and areas into a drawing. Objects may be created free hand or pre-built shapes may be inserted.

 

·      To create areas, lines or points, simply choose the appropriate Insert command and draw the desired shape using left mouse clicks. A right mouse click indicates you are finished and the shape is to be created.

·      To create a pre-built shape, choose the shape command desired and then click and drag open a mouse box showing the placement and size of the desired shape.

 

Shape mode buttons allow automatic creation of the shapes using areas, lines, points or any combination of the three.

 

See the Adding Points, Lines and Areas topic for additional details and examples. See the Instant Data topic to learn how to quickly add data attributes when creating an object.

 

Insert Area

images\btn_shp_area.gif

Draw areas within the mouse cursor region defined by a series of clicks followed by a right click.

Insert Freeform Area

images\btn_shp_freeform_area.gif

Draw areas within the mouse cursor region defined by clicking and dragging, followed by a right click.

Insert Freeform Line

images\btn_shp_freeform_line.gif

Draw lines as defined by clicking and dragging, followed by a right click.

Insert Line

images\btn_shp_line.gif

Draw lines as defined by a series of clicks followed by a right click.

Insert Line Sequence

images\btn_shp_lineseq.gif

Draw lines as a sequence of separate lines.

Insert Point

images\btn_shp_point.gif

Draw points - click to create a point.

Insert Box

images\btn_shp_box.gif

Draw a rectangular box shape with a click and a drag.

Insert Box on Center

images\btn_shp_cbox.gif

Draw a rectangular box shape centered on initial mouse click.

Insert Circle

images\btn_shp_circ.gif

Draw a circle with a click and a drag..

Insert Circle on Center

images\btn_shp_ccirc.gif

Draw a circle centered on initial mouse click.

Insert Ellipse

images\btn_shp_ellip.gif

Draw an ellipse with a click and a drag..

Insert Ellipse on Center

images\btn_shp_cellip.gif

Draw an ellipse centered on initial mouse click.

Insert Geographic Circle

images\btn_shp_geocirc.gif

Draw a shape centered on the initial mouse click that forms a circle on the Earth. That is, each location on the shape will be the same distance from the center point. May appear to be a non-circular shape depending on the projection of the drawing.

Create Areas

images\btn_shpmodearea.gif

Create areas when drawing shapes.

Create Lines

images\btn_shpmodeline.gif

Create lines when drawing shapes.

Create Points

images\btn_shpmodepoint.gif

Create points when drawing shapes.

 

Shape Modes

 

images\btns_shpmodes00.gif The shape mode buttons specify what types of objects should be created when a shape is drawn. Push in the mode button for the type of object desired. For example, if both the Area and the Point buttons are pushed in, then any circles or other shapes drawn will be created using both area objects as well as points at the coordinates defining the shape. This is an extremely useful effect for simultaneously creating area and line objects for complex shapes.

 

The following examples create the same star shape using Insert Area but with different combinations of shape mode buttons:

 

 

Areas

 

images\btns_shpmodes02.gif

images\sc_shapemode02.gif

 

 

 

Lines

 

images\btns_shpmodes03.gif

images\sc_shapemode03.gif

 

 

 

Points

 

images\btns_shpmodes04.gif

images\sc_shapemode04.gif

 

 

 

Lines and Points

 

images\btns_shpmodes05.gif

images\sc_shapemode05.gif

 

 

 

Areas and Lines

 

images\btns_shpmodes06.gif

images\sc_shapemode06.gif

 

 

 

Areas and Points

 

images\btns_shpmodes07.gif

images\sc_shapemode07.gif

 

 

 

Areas, Lines and Points

 

images\btns_shpmodes01.gif

images\sc_shapemode01.gif

 

 

 

Automatic Shape Modes

 

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 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.

 

Shapes, Geographic Circles and Coordinate Systems

 

With the exception of the Insert Geographic Circle command, all shapes are drawn using the local coordinate system of the drawing. That means that when we insert a circle using the Insert Circle tool a circle is drawn on the XY plane of whatever coordinate system is in use. The result is exactly the same as if we drew a circle on a paper map showing the same region with the same projection.

 

In many cases, if we are viewing a reasonably small region and the projection in use preserves lengths and other geographic characteristics (and projections are normally chosen so as to preserve such characteristics), drawing a circle in that region will be very close to the shape of a true circle drawn on the Earth's surface at that region. However, because it is not possible to represent the three dimensional, ellipsoidal shape of the Earth in a two dimensional plane (such as a paper map or a computer monitor) without distortion if we draw a circle on a projected map showing a large region of the Earth the figure we draw will not form an actual circle on the surface of the Earth.

 

To draw a circle that is guaranteed to be a circle no matter what projection is in use we should use the Insert Geographic Circle command. This command allows us to draw a circle of given Earth radius centered on a specified location. The actual shape created in the projected view may be considerably different than a circle depending upon the distortion introduced by the projection, but the object will be a true circle on the Earth's surface.

 

Example

 

Consider a map of the Earth drawn in Sinusoidal projection.

 

images\eg_insert_geocirc_01.gif

 

Regions far from the center of the map are significantly distorted. In the above illustration we've added a point on the Southwest coast of Australia.

 

Using Snap to Point we use the Insert Geographic Circle tool to create a circle centered on that point.

 

images\eg_insert_geocirc_02.gif

 

The Geographic Circle dialog will open already loaded with the coordinates of the central point in the local coordinate system. We choose a radius of 1000 miles and set the number of divisions to 64 to create a nice, smooth object. Press OK.

 

images\eg_insert_geocirc_03.gif

 

The result is that a very non-circular object appears in the drawing. However, the object has been calculated so that if we looked at it from directly overhead, that is, with none of the distortion introduced by the Sinusoidal projection, it would be a circle.

 

images\eg_insert_geocirc_04.gif

 

We can see that is the case by re-projecting the map into Orthographic projection centered on the point that was the center for the geographic circle.

 

(We can find the latitude / longitude of the point by snapping the cursor to the point and reading the lat/lon value on the status bar. For a cleaner map image in the illustration above, we've also re-projected the drawings used and clipped coordinates.)

 

The Orthographic projection shows us what we would see on the Earth's surface if we were hovering in space over the central point. Clearly, the object created is indeed a circle on the Earth.

 

images\eg_insert_geocirc_05.gif

 

To see how the Insert Geographic Circle command differs from the Insert Circle command, we can use the Insert Circle command to create a freehand circle above and to the right of the geographic circle.

 

Note that in the projected view, the circle we have created appears to be a circle. However, it is just as if we had drawn a circle in that location on a paper map that used the Orthographic projection. The region of the Earth that is covered by a circular figure drawn on such a projection map is not a geographic circle.

 

images\eg_insert_geocirc_06.gif

 

If we re-project the map view to use an Orthographic projection centered upon the approximate center of the new "circle" we drew, we can see that the object we drew does not cover a circular region of the Earth.

 

Tech Tip

 

To avoid confusion, it is best to use Insert Geographic Circle with projected drawings and maps. If used with latitude / longitude coordinate systems the results can be confusing because degrees are different sized in different parts of the Earth.

 

See Also

 

·      See the Snap To topic for information on using Snap to snap the cursor to exact locations.

·      See the Autocomplete with ALT for an important shortcut in the Insert Area and Insert Line commands when creating areas or lines that fit exactly into existing areas or lines.

·      See the Dialog Mode and Visual Tools topic for a parameter or value oriented way of creating objects.