FROS Routine

The FROS Routine is intended to establish frontage points, (or rear alignment points), along a straight line.

Only one frontage line may be handled with a single FROS heading, - however, a maximum of 25 points may be established on that frontage line. The known starting point on the line is entered under known point, course A, and the bearing of the line is entered in course B, (note only the bearing and not a bearing course). The required point is entered under the unknown point heading, and the distance from the known point in course A, (this requires course A to be a distance course).

Each subsequent entry under the same FROS heading defines another point on that frontage line. In such cases the required point is entered in the unknown column, and the distance, from the last established point, in course A.

A facility exists in FROS for computing a sequence of consecutive point numbers spaced at equal intervals along a frontage line by using the auxiliary point number. The unknown point is spaced from the known point at the distance specified, the unknown point number is then increased by 1 and computed at the same spacing distance from the last computed point. This process is continued until the auxiliary point number is reached. The next line of coding on the input form is then checked, and if it is still under the same FROS heading, the process is continued, (possibly on different spacings or as defined).

An example of a FROS operation is shown below. Point 220 is defined as 18.0 from 104 on bearing 104 to 100. Point 221 is 220.0 from 220, point 222 is 18.1 from 221, point 223 is 18.1 from 222. Now comes the easy part, points 224 through 228 inclusive are defined as 18.0 metres apart.

A maximum of 25 consecutive points may be established using the multiple point generation facility.

       XY Data Point Record          Col 
           Record Type  02           1
                Routine FROS         2
          Unknown Point ____         3
 Course A - Known Point ____         4
                Bearing _______      5
               Code (P) _            6
               Distance __________   7
              Indicator _            8
                Point 1 ____         9
                Point 2 ____         10
 Course B - Known Point ____         11
                Bearing _______      12
               Code (P) _            13
               Distance __________   14
              Indicator _            15
                Point 1 ____         16
                Point 2 ____         17
        Auxiliary Point ____         18