@article{fdi:010074915,
  title = {{T}opography of the intertidal zone along the shoreline of {C}hittagong ({B}angladesh) using {PROBA}-{V} imagery},
  author = {{B}ergmann, {M}. and {D}urand, {F}abien and {K}rien, {Y}ann and {K}han, {M}. {J}. {U}. and {I}shaque, {M}. and {T}estut, {L}aurent and {C}almant, {S}t{\'e}phane and {M}aisongrande, {P}. and {I}slam, {A}kms and {P}apa, {F}abrice and {O}uillon, {S}ylvain},
  editor = {},
  language = {{ENG}},
  abstract = {{A}cross the oceans shorelines, monitoring the topography of the intertidal zone is generally challenging. {T}he present study is motivated by the recognized role of the intertidal topography in the near-shore hydrodynamics. {W}e consider the region of {C}hittagong (northern {B}ay of {B}engal) because of its propensity to powerful cyclone surges and associated inundation hazard. {S}o as to curb the lack of in situ knowledge of intertidal topography, we present an original procedure relying on spaceborne optical imagery. {O}ur method essentially amounts to a water line detection performed at various tidal levels. {W}e apply our procedure to the recent {PROBA}-{V} ({P}roject for {O}n-{B}oard {A}utonomy-{V}egetation) multi-spectral imagery mission. {T}he first step of our procedure concerns the shoreline extraction. {PROBA}-{V} imagery consists of four bands ({R}ed, {B}lue, near-infrared - {NIR}, short-wave infrared - {SWIR}), which are then combined to generate an artificial red-green-blue ({RGB}) image. {T}his {RGB} image is then converted into the hue-saturation-value ({HSV}) colour space. {A} simple thresholding is applied to hue and value channels to separate water masses from land masses. {T}his process is applied to several images taken at different water levels (i.e. different parts of the tidal cycle) and the corresponding water lines are inferred. {T}o estimate the altitude level of the water lines, we rely on tidal observations from two gauges located at {C}hittagong and {C}ox's {B}azar. {W}e operate an ad-hoc extrapolation of the point-wise gauge data to generate a synthetic tidal water level record all along the shoreline. {T}hese synthetic tidal heights are then combined with the shorelines to generate the final digital elevation model ({DEM}). {T}he {DEM} we generated covers a 40-km long stretch of shoreline around {C}hittagong city. {W}e assessed this {DEM} by comparison with two independent data sets based on in situ surveys as well as on {P}leiades spaceborne stereoscopy. {W}e conclude that our {DEM} is accurate within 1 m to 2 m, which is within the error bar of these validation data sets. {O}ur procedure being essentially objective, it is easy to automate, for processing of other imagery satellite, including at high resolution and/or in real time.},
  keywords = {{BANGLADESH} ; {CHITTAGONG} ; {BENGALE} {GOLFE}},
  booktitle = {},
  journal = {{I}nternational {J}ournal of {R}emote {S}ensing},
  volume = {39},
  numero = {23},
  pages = {9004--9024},
  ISSN = {0143-1161},
  year = {2018},
  DOI = {10.1080/01431161.2018.1504341},
  URL = {https://www.documentation.ird.fr/hor/fdi:010074915},
}