This app was designed for the purposes of recording dumpy level surveys usually performed by hydrographers or surveyors. It is available on both iOS and Android and works fully offline with no internet required.
The aim is to facilitate record taking and calculations. Errors are commonly attributed to arithmetic mishaps or incorrect operations between readings. This app takes over the task of calculating rises and falls between measurements, as well as giving absolute elevations based on a known starting point.
The app is available as a FREE TRIAL for 7 days, then as a subscription for $4.99 per month or $49.99 per year.
You can download the app from iOS and Android using the links below:
The Survey Details screen is where you would enter meta data about the particular site. At a minumum a Site Name and a Date is required to proceed to the next screen
The first Survey Entry screen asks for a seed level. This is normally a known elevation for a particular point in space. These are commonly registered benchmark with known elevations. However they can also be arbitrary values (e.g. 100.000) if elevation is unknown. The first entry is ALWAYS a backsight entry.
As you progress through the survey you may add intermediate points. These are points of interest where you want to know the elevation. They are called intermediates because the position of the dumpy has not moved since the last backsight reading.
Once you wish to move the dumpy, you will need to use BS + FS button to record a change point. Enter the FORESIGHT value, move the dumpy, then shoot back to the same location and enter that number as BACKSIGHT. It would be wise to note in remarks that this is change point
You will notice rises and falls between each point as well as the datum (elevation) of each point. To close the survey, you will need to shoot back to the starting point and record that as a FORESIGHT. Surveys always end on a foresight and start on a backsight. The number next to Diff on the bottom right refers to the difference between the sum of BACKSIGHTS and the sum of FORESIGHTS. This is referred to as Misclose
When you choose finish survey, you will get a summary of the entire survey as well as your MISCLOSE value. This value will turn green with a tick if the misclose (in millimeters) is less than 2 times the square root of the number of change points. Otherwise it will turn red with a cross indicating a misread or user error somewhere in the survey.
NOTE: this is available in real-time on each reading you take.
Above is an example of a saved survey in PDF format. This is saved to the device, on the previous screen you may then share through third party apps (e.g. email, teams, drive, dropbox, icloud, whatsapp etc). JSON and CSV format are used for ingestion into other databases
There is an option to add chainage values to each reading. With most electronic dumpy levels they will output an Electronic Distance Measurement (EDM). You can check the box to enable chainage to be recorded if that is part of the work plan. No calculations are performed on chainage, it is purely a repository of the value for the EDM.
A running total of the backsight and foresight values on each screen are given. This is an indication on the accuracy of the survey, the closer the totals of backsights and foresights are the better. The difference between these values are referred to as MISCLOSE, and the app gives you a running total of misclose. The app will indicate if the mislcose number is acceptable, based on number of change points in the survey.