Home > Survey Mode > Reductions > Tache > Fieldbook > New Field Book
Tache data can be typed directly into the spreadsheet. Each line of the spreadsheet represents a setup station, an outward orienting ray or a tache observation. Tache observations can either be an EDM or prism observation, a tache or staff observation, or a polar observation (generally from a total station).
Each type of entry has different requirements. All entries require at least a field book indicator code (see below) and a point name.
Setup stations also require an instrument height.
Outward orienting rays also require a horizontal angle reading.
EDM or Tache observations also require a horizontal angle reading, vertical angle reading, a distance and a target height (stadia or prism).
Polar observations also require a horizontal angle reading, a distance and a height difference (instead of the prism height).
Permissible field book indicator codes are:
{ - Setup station
% - Outward orienting ray
e - EDM (or prism) observation
t - Tache (or staff) observation
The order of the data fields is:
Indicator code
Setup name or target point descriptor
Horizontal angle reading
Vertical angle reading
Slope distance
The following is a listing of a typical Tache field book:
{,T1,0.0000,0.0000,0.000,1.642
%,P4,0.0000,0.0000,0.000,0.000
%,P2,304.2013,0.0000,0.000,0.000
e,Re,289.4158,86.1946,30.794,1.940
e,Re,295.1743,86.0412,27.756,1.940
e,Re,276.1219,86.4122,19.585,1.940
t,RDWe,182.4556,86.2919,8.880,2.000
t,Re,138.5245,89.2622,46.823,3.400
p,TRIG,345.1734,81.4520,294.785,13.254
The first line is a set-up station called 'T1' and the instrument height is 1.642.
The second line is an orienting ray to 'P4'.
The third line is an orienting ray to 'P2'.
The next three lines are EDM observations to a feature described as 'Re'.
The next two lines are staff observations.
The last line is a Polar observation where the final item is a height difference. The vertical angle is always ignored and ninety degrees used instead, forcing the distance to be a flat distance.
A "p" code causes the vertical angle to be ignored and the reduction calculation performed as though the distance is flat. It is the equivalent of using a 90 degree vertical angle, but without the necessity of entering it as such. It is used primarily with total stations that export fully reduced horizontal distances and height differences. The height difference measurement and the instrument height are added to the setup station's elevation to get the observed point's elevation. You therefore need to incorporate any prism height into either the height difference measurement or the instrument height.
Curvature and refraction corrections are automatically applied. Sea level, scale and temperature corrections ARE applied if selected ON.