There are seven methods of displaying circular shapes. The first three of these create a circle from one point together with an additional dimension.
1 Pt Circle - This option creates a circle from a surveyed centre point and a measured radius. The radius of the circle is provided in the Radius dimension, normally R=.
1 Pt Diameter - This option creates a circle from a surveyed centre point and a measured diameter. The diameter of the circle is provided in the Diameter dimension, normally D=.
1 Pt Circumference - This option creates a circle from a surveyed centre point and a measured circumference or girth. The circumference of the circle is provided in the Circumference dimension, normally C=.
1 Pt Circle |
1 Pt Diameter |
1 Pt Circumference |
The Adjust Survey Distances check button also applies to circles that can be constructed from one point. If this button is ticked, the value of the radius of the circle is added to the observed distance during the survey reduction process. If this button is not checked, the displayed point will not be adjusted so that it is in the centre of the circle unless you also specify a distance offset dimension, normally H=. This check button removes the need to duplicate information by providing a means of calculating a radius and the distance offset dimension, both of which are the same value.
The Alternate Points check button also applies to the circles that can be constructed from one point. As the name suggests, this option allows you to only display a circle on every other point. An example of this is a where a tree has been surveyed using two points, the first on the trunk and the second on the edge of the canopy. If you want to use a 1-point circular shape to show the size of the trunk, this stops the display of a second trunk at the canopy edge.
Four further method create circular shapes from two or three points.
2 Pt Circle - This option creates a circle from a surveyed centre point and a second surveyed point anywhere on the circumference of the circle.
2 Pt Diameter - This option creates a circle from two points on the circumference of a circle. The points will be assumed to be diametrically opposite each other.
3 Pt Circle - This option creates a circle from three points. Each of the points should be on the circumference of the circle.
3 Pt Arc - This option creates an arc from three points. The arc will be drawn from the first point to the third whilst passing through the second. This type of shape is often used in building elevation surveys to represent arched lintels above doors and windows.
2 Pt Circle |
2 Pt Diameter |
3 Pt Circle |
3 Pt Arc |
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