Working with Areas

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Working with Areas

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.

Double Meridian Distance

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.

Curve and Spiral Segments

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.

Special Road Considerations

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 accommodate this by temporarily 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.

Area Types

TPC determines whether to compute a grid, ground or geodetic area based on the Distance Type

Closure View

The Closure View 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.

Lot Labels

Within the Drawing View, Drawing and Traverse Drawing 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.

Legal Descriptions

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.

Traverse Data Printouts

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 ]]

Predetermined Areas

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.

Drawing View

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,

•Choose Edit | Drawing Settings, Miscellaneous.

•Turn on Compute Area.

Polylines

Beginning with TPC Desktop 2018, you can compute the area of a drawing polyline in the Polyline Properties dialog. This area is then displayed in the polyline's tooltip and in the Drawing Data Manager when you

Area Settings

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).