TPC Technote

Scale Factors

TPC has four tools for working with scale factors. These tools allow you to control the scale of both the coordinates and the distance values generated from those coordinates.

Coordinate Conversion

The coordinate conversion tool is available from the Tools menu of the Survey View. It allows you to scale the entire survey toward or away from the origin 0,0. TPC multiplies every coordinate value, raw distance, radius, etc. by the amount you specify.

The most common use of this tool is to convert a survey from one unit to another (i.e. feet to meters), but it can also be used to apply a grid factor or elevation factor to a survey.

If you convert from imperial to metric, TPC gives scale and paper sizes in metric vs. imperial units.

Traverse Scale Adjustment

Apply Scale Factor is available from the Adjust menu of the Closure View. It factors the length of each course or line in a traverse, including side shots. The scale factor is recorded along with the other adjustments, and can always be undone to get back to the raw coordinates.

The most common use of this tool is to add a traverse based on local grid or measured distances to a survey that is based on a MSL or state plane grid.

Traverse View Distance Factor

The distance factor is available in the Traverse View Format dialog box. It only affects distances shown in Inverse mode, where the distances are computed by inversing between coordinates.

The formula used to display distances is: displayed dist = inversed dist / dist factor.

The distance factor also affects how the coordinates are computed, much like the scale factor in the Closure View. As TPC computes a traverse, it uses the formula: computed dist = raw dist X dist factor.

The most common use of this tool is to convert a measured distance to the units of the survey. For example, if you want to enter GLO data in chains into a survey that is in feet, enter a distance factor of 66.

The distance factor is printed with the traverse name when you choose Print from the Traverse Screen. It is also displayed on the bottom line of the Traverse Screen as DF=XXX. Each traverse remembers its own distance factor. The default value is 1.00000.

Quick View Distance Factor

The Quick View has a distance factor of its own that affects only the distance labels of the lines. To edit the distance factor, go to Edit | Drawing Settings - Miscellaneous tab.

If your survey units are in feet and you want to annotate lines with chains, enter 66 for the distance factor. The factor you enter here does not change any coordinates and does not affect the distance factor in any traverses.