Reduction

Reduce Surveys

The Reduction option to reduce your download survey pickup data into a design database layer, splitting the data into strings and points based on the survey codes attached to the data during pickup. This option is mainly used when your downloaded pickup data is in radiation form (horizontal angle, vertical angle and slope distance). During the reduction, the survey.codes file is used to determine naming, colouring conventions etc.

The survey.codes file is created and edited using the Edit Codes option and contains the following information:

• Object name for the string or point (For example, crest, toes).
• Group name.
• Feature name.
• Colour.
• Line type.
• Points or lines.

An example is given in Appendix A.

All reduced objects in the design database are given an object description that can be used as a trace record to track the object back to its source job. The trace record consists of the following:

• Job name.
• Date.
• Surveyor's name.
• Assistant surveyor's name (optional).

Note:   In the case of a GEODAT instrument, code 55 value (instrument ID) will be appended to the object description of reduced objects.

Different instruments may, or may not, have this information encoded into the download survey pickup data. If the pickup data doesn't contain the information coded in the form that Vulcan requires, then enter the default values in the text entry boxes on the main download panels.

The Reduction options vary depending on the instrument selected. Some of the more advanced options are:

• WILD/LEICA and GEODAT instruments can define temporary stations that are picked up during the job and then occupied. These are searched for last when trying to find the coordinates of the instrument or backsight station. These can be optionally saved in a station library at the end of the reduction if required.
• WILD/LEICA and GEODAT instruments can define a shot to be a check shot to a known station. This means that a misclose will appear on the report for that shot.
• Specifically formatted GEODAT files can contain a resection followed by shots. This is detected by the Reduction option, which will then process the resection in a manner similar to the Resection option, but will then continue on and perform the reduction in one step.

Note:  The [Esc] key can be selected at any time in the reduction process to stop reducing further points.

Instructions

• Select Survey menu
• Select Surveying submenu
• Select Reduction option

The panels that are then displayed depend on the instrument being used.

GRE4
GIF10
GEODAT
SDR 22
SDR 33
LEICA_TPS1000
CRTR400
TOPCON TPS-7