Home > Survey Mode > Reductions > Tache Sections > Fieldbook > New Field Book
Open a new, blank spreadsheet for Tache Section data.
Tache Section data can be typed directly into the spreadsheet. Each line of the spreadsheet represents a header entry, a setup station or a section observation. Tache section observations can either be an EDM or prism observation, or a tache or staff observation.
Each type of entry has different requirements. All entries require at least a fieldbook indicator code (see below) and a point name or descriptor.
Header lines also require a section chainage. Setup stations require in addition an instrument height.
EDM or Tache observations also require a vertical angle reading, a slope distance and a target height (stadia or prism).
Permissible field book indicator codes are:
# - Header line for section start
{ - Setup station
e - EDM (or prism) observation
The theodolite must be set up at a station somewhere along the cross-section. Up to 11 setup stations can be occupied per cross-section, but must conform to a naming convention. The reserved names for the setup stations are as follows:
CL - Setup station on the horizontal alignment centreline.
L1 through to L5 - Setup stations to the left of the horizontal alignment.
R1 through to R5 - Setup stations to the right of the horizontal alignment.
Although the elevation of the CL point is used as the datum for the reduction of the observations, it is not necessary to physically occupy it. An observation can be taken from one of the other setup stations to the CL.
Observations can be made from any number of the setup stations, in any order, as long as they are referenced to one another in some way and ultimately with CL. For example, it is possible to set up at a station L1 and take observations, move to a station R1 and take more observations but also observe L1 and CL at this set-up. In this way, L1 is referenced to CL via L1's connection to R1.
Each observation of a section point must have an ' L' as the first letter of the comment for an observation left of the current set-up station, or an ' R' if it is to the right of the current set-up station. If the observation needs further comment it should be separated from the first letter by '/ ' e.g. 'L/ER' or 'R/TB'.
The order of the data fields is:
Indicator code
Setup name or target point descriptor
Vertical angle reading
Slope distance or section chainage
Instrument or target height (Stadia or prism)
The following is a listing of one cross-section in a field book:
#,,0.0000,2160.000,0.000
{,CL,0.0000,0.000,1.570
t,L/BB,97.2000,14.500,1.170
e,L/TB,97.1800,16.200,0.680
e,R,270.3800,16.100,0.780
t,R,272.2400,18.000,1.400
t,L1,97.1100,22.000,1.200
{,L1,0.0000,0.000,1.530
t,L/ER,89.2300,2.000,1.100
The first line denotes the start of a cross-section at chainage 2160
The second line is a set-up at CL with an instrument height of 1.570
The next two lines are observations are to the left of CL (with comments 'BB' and 'TB').
The next two lines are observations to the right of CL
The seventh line is an observation to the next set-up station L1 (First station to the left)
The eighth line is a set-up at L1 with an instrument height of 1.530
The last line is an observation to a point 'ER' that is to the left of L1
The next cross-section should follow directly after the last observation of the current section.