home

about us

our products

our services

contact us

 

EDM Target System - Users Explanation

At the start of the job each target is surveyed and the Eastings, Northings and Level are recorded as the Base Readings.

At specified intervals (normally daily) the targets are resurveyed and the results recorded electronically.

The daily results are compared with the Base Readings and (by subtracting one from the other) a difference in levels and position (Eastings and Northings) can be determined (i.e. Original value minus new value, this can be done using a spreadsheet). By adding/subtracting these differences in levels to the original cant and twist values, a new cant and twist value for the tracks can be obtained for each day. By inserting these daily values into a table any trends can be easily spotted, using the spreadsheet formatting options it is possible to highlight any changes greater than a set amount (e.g. any change greater than say plus or minus 5mm will be highlighted in say orange, any change greater than say 10mm can be shown in red).

Again, using the facilities within the spreadsheet, reports, charts and graphs can easily be produced showing daily movements and, if required, long term movements of each surveyed point or group of points in any axis.

A spreadsheet is used to show a set of daily readings compared to the design cant and the actual cant at the start of a job. As there are two lines at this location, it also shows the interval between the two tracks compared to the original value. It will be noted that only the Eastings and Levels are used, as the grid for this site was arranged so that the Northings values were along the track and are therefore irrelevant.