Traversing with Historic Scotland

Historic Scotland are investing in survey! As part of their development of a minimum site record we do a training exercise in travserse control. I am asked to trouble-shoot their field kit, update to TheoLtr8.1.6 and take 3 teams through network observation and adjustment. The practice site is Blackness Castle and the weather is cold but, mercifully, dry.

We rattle through setting up, do a 4 stn loop, make a mess of station naming, recover and head off to the paraffin perfumed barrack block to check the results. We work through our data and run the calc, the results are superb! The network is adjusted and applied and we enjoy a good buffet lunch before tackling 3 networks in 3 teams.

The new station name editing feature has improved using user defined station names at capture. The great thing about netadjust in TheoLt is the real-time aspect, poor shots are flagged as measured and preview calculations and diagrams can be run, all on live data. Traversing is all about procedure and adapting to new ways of working can make simple things difficult, it always takes patience to get procedures right and we have to make a few re-starts before we get the sequence to suit the situation.

Taking out the ‘brown’ data is a good starting point for analsing the network.

Taking out the poor shots, running the calc and seeing the result can prompt you to take more obs or, in this case,  shave 10ths of a mil off an adjusted station position: a far cry from the days of Bowditch and the calculator!

Because TheoLt works with live station properties station names have been on a like- it -or- lump- it basis until release 8 when it bemame possible to use a custon station name. This is a surprisingly useful improvment as there occasions when station names are pre-set from existing survey or when station ocupation is in decending order, in the past renaming was only possible as an AutoCAD edit post-survey, now the name can be set at Default Orientation or when the station is set out.

Customisable station naming is one method of working with pre-declared station identities, station names can now be determined at setting out adding a new level flexibility to  control operations.

This relatively simple addition to the functionality of Netadjust in TheoLt 8 has a great impact on workflow. Whether you are occupying existing control, adding stations to an existing network or creating a new network from scratch, Theolt now affords the Surveyor the optimum realtime platform for Control networks.

TheoLt Real-Time Network Adjustment offers a new workflow whereby the network benefits from:

  • Review of each observation- Interactive rejection of observations with real-time results update
  • The ability to ensure each station is complete before moving
  • Computation of Resections with multiple face oberservations.
  • Adjustment of CAD drawings to network- Live diagram in CAD

So before you put your kit back in the box you can be sure your network is delivering what you need!

What is the difference beteween Leica’s Disto to CAD tool and DistToPlan?

The Leica DISTO transfer has been available now for a while on both AutoCAD and BricsCAD.

With the advent of the new cheaper Bluetooth Distos (3aBT) which includes this free tool I would expect far more surveyors to be investigating the transfer of measurements direct to CAD whilst on site.

So, what is the difference between this free tool and DistToPlan (which of course is not free)? I will compare like with like. The Leica tool is only a communication agent so I will compare this with the DistToPlan agent.


DistToPlan works with any Bluetooth driver by default. All that is required is to select the virtual com port ( ports 1 to 8 ) and connection will be established. With the Leica system, if the the bluetooth driver is neither the Broadcom or Microsoft drivers an additional configuration program must be run to allow  manual connection to be established. If the correct drivers are installed the Leica software will automatically find the Disto.

The DistToPlan agent is an external EXE, selecting the settings enables the CAD Platform to be selected (AutoCAD, Bricscad or InteliCAD). In addition DistToPlan my be customised to send the measurements to almost any Windows application. Only AutoCAD® versions from 2004 and BricsCAD® versions from 9.3.5 are supported by the Leica PlugIn.

In Use:

The Leica system allows customisation of the Disto device such as units remotely which DistToPlan does not.

Both applications transfer the measurements direct from the Disto to the CAD command line as if they were typed. The main difference is that DistToPlan also stores the previous measurements (and angles, see below), meaning that the command in CAD need not be active as you measure, it is possible to measure the room and then sit at the laptop picking the correct dimensions for each line.

With the 2nd fn key pressed on on the Disto, both systems allow the angle of the line to be controlled from the Disto whilst measuring.

One further function that does not seem to be offered by the Lecia software is remote trigger. If you wish to use the Disto on a pole for example, DistToPlan is able to trigger a measurement remotely.

The extent of the Leica software is simply data transfer. DistToPlan adds a full set of commands to the CAD system to enable construction of building plans far quicker than just utilising the basic CAD commands. Examples of this may be seen here…

DistToPlan may be downloaded here…