TY - JOUR
T1 - MEASURING WATER LEVELS BY HANDHELD SMARTPHONES – A contribution to exploit crowdsourcing in the spatio temporal densification of water gauging networks
AU - Elias, M.
AU - Maas, H.-G.
JO - The International Hydrographic Review
VL - 27
SP - 9
EP - 22
PY - 2022
DA - 2022/05/31
DO - https://doi.org/10.58440/ihr-27-a01
UR - https://ihr.iho.int/articles/measuring-water-levels-by-handled-smartphones-a-contribution-to-exploit-crowdsourcing-in-the-spatio-temporal-denisificatiion-of-water-gauging-networks/
KW - crowdsourcing
KW - flood event
KW - image processing
KW - low-cost
KW - Photogrammetry
KW - smartphone application
KW - water level measurement
AB - Global climate change leads to an increase in local heavy rainfall events causing nearly unpredictable flash floods worldwide. This paper introduces a novel and flexible low-cost water gauging technology, called Open Water Levels, using smartphones as low-cost measuring devices enabling the crowdsourcing of water levels on demand with accuracies of a few centimetres. This merely requires smartphone camera images of a riverbank and approximate values of the camera position and rotation measured by smartphone sensors. The images are analysed for the water line that is further projected into object space and intersected with a 3D model, e.g. from a GIS database, to derive water level information.