TPC can compute the area of any closed loop traverse. It uses a coordinate method, subtracting the easting of the first area point from the easting of all the other area points to eliminate potential floating-point errors that could result from using State-Plane type easting values.
The program reports and uses areas in a number of places in the program. Most of these compute the area of a traverse as needed.
TPC uses the double meridian distance method (DMD) to compute areas. Information about this method is available in most surveying textbooks and is not discussed here. If you are familiar with this method, you know that it assumes tangents between adjacent boundary points, so curve and spiral segments need to be added or subtracted where they are encountered.
TPC can compute grid areas or geodetic areas which account the ellipsoid surface.
In the process of generating a DMD area, TPC determines whether the traverse is run Clockwise or Counter-clockwise. As curve and spiral segments are encountered, they are added or subtracted from the DMD area as appropriate, based on the traverse direction.
In some situations, where the area is computed for a road way, it is possible for part of the desired area being computed lies within the segment of one or more long curves defining the road right-of-way. TPC can accomodate this by remporarily partitioning long curves into shorter segments, this eliminating any segment overlap of the desired area. This is a manual setting which can be turned on as needed for any traverse in the Traverse Format dialog.
TPC determines whether to compute a grid, ground or geodetic area based on the
Distance Type
The Closure Vieww displays the area of any closed
loop traverse in square units (feet or meters) and area units (acres or hectares).
The area of a closed loop is computed from the Initial Point to the Closing Point.
If these points do not have the same coordinates (the loop doesn't close), TPC connects
the two points with an imaginary line and computes the resulting area of the loop.
Each time you open the Closure View and also when you choose View |
Refresh, TPC recomputes the area of the traverse.
Area is not computed for Closed-Point-To-Point and Open traverses.
Within the Drawing View Drawing and Traverse Settings, you can turn on lot labels
that include the area of the traverses and display it as a lot label, either in
square units (feet or meters) or area units (acres or hectares).
These lot areas can be computed automatically (slows down the regen process) or
manually. To turn on automatic area computations choose Edit | Drawing Settings,
Miscellaneous and turn on the [X] Compute Area toggle.
When you create a legal description from a closed loop traverse, you can include
the area of the traverse in square feet, square meters, acres or hectares at the
end of the description. In the Legal Description
dialog, turn on the [X] SqFt or [X] SqMeters toggle or the [X] Acres or
[X] Hectares toggle.
TPC includes the area of a closed loop traverse in the report heading as in the
following example.
[[ Traverse: Example Traverse Area: 54154.32 SqFt 1.24 Acres Distance Factor: 1.000000000
]]
TPC can create a traverse of some specified area from any closed loop traverse.
You use the Predetermined Area dialog
to specify the area you want and the method to use. TPC creates a new traverse of
the area specified and can place the reminding area in another traverse.
By default, Drawing View uses the last area computed for a traverse. If a traverse
area has not yet been computed, Drawing View will compute it, then display it.
If you are editing the area of a traverse frequently and want Drawing View to compute
the current area,
Several user defined area settings are available in the Program Settings dialog
on the Units page. You can specify what text
to use for square units (FT2, SqFt, SF, etc) and Area (Acres, AC, etc).
Working with Survey Files
Property, Personal, Premium, Professional
Closure View
Lot Labels
Legal Descriptions
Traverse Data Printouts
Predetermined Areas
Drawing View
Area Settings
Related Topics
Geodetic Area
Editions