On digital levelling technique applied in water crossing
Takalo, Mikko and Paavo Rouhiainen
The digital levelling technique is commonly applied in precise levelling today. In Finland the longest sighting distances in precise levelling are 50 m, but sometimes the longer sightings are needed, e.g., in water crossings over the lakes, valleys or rivers. The Zeiss DiNi12 digital levelling system is capable to operate until to 100 m, but in water crossings we need longer sightings. Basically, the bar code scale of the rod can be copied with a certain magnification and thus be enabled to use longer sighting distances. According to the tests the Zeiss DiNi12 was able to process rod readings at the distances even to 400 m. − A new rod pair, in which the bar code scale was magnified 4 times, was constructed. To study the operational terms and accuracy of the Zeiss DiNi12 in the water crossing circumstances, a special test field with 250 m, 350 m and 400 m sighting distances was constructed. Results obtained verified that the developed digital water crossing method fulfills the requirements of the precise levelling. − A trigonometric levelling method applied in water crossing was also studied. The results were promising.
Event: XXIII International FIG Congress : Shaping the change
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