Detecting end-member structural and biological elements of a coral reef using a single-beam acoustic ground discrimination system
| العنوان: | Detecting end-member structural and biological elements of a coral reef using a single-beam acoustic ground discrimination system |
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| المؤلفون: | Bernhard Riegl, Victor S Ticzon, Greg Foster, Peter J. Mumby |
| المصدر: | International Journal of Remote Sensing. 32:7749-7776 |
| بيانات النشر: | Informa UK Limited, 2011. |
| سنة النشر: | 2011 |
| مصطلحات موضوعية: | geography, geography.geographical_feature_category, Coral reef, Sonar, Footprint, Echo sounding, Thematic map, Benthos, Benthic zone, General Earth and Planetary Sciences, Satellite imagery, Cartography, Geology, Remote sensing |
| الوصف: | A thematic map of benthic habitat was produced for a coral reef in the Republic of Palau, utilizing hydroacoustic data acquired with a BioSonics DT-X echosounder and a single-beam 418 kHz digital transducer. This article describes and assesses a supervised classification scheme that used a series of three discriminant analyses DAs to refine training samples into end-member structural and biological elements utilizing E1′ leading edge of first echo, E1 trailing edge of first echo, E2 complete second echo, fractal dimension first echo shape and depth as predictor variables. Hydroacoustic training samples were assigned to one of six predefined groups based on the plurality of benthic elements sand, sparse submerged aquatic vegetation SAV rubble, pavement, rugose hardbottom, branching coral that were visually estimated from spatially co-located ground-truthing videos. Records that classified incorrectly or failed to exceed a minimum probability of group membership were removed from the training data set until only ‘pure’ end-member records remained. This refinement of ‘mixed’ training samples circumvented the dilemma typically imposed by the benthic heterogeneity of coral reefs, that is either train the acoustic ground discrimination system AGDS on homogeneous benthos and leave the heterogeneous benthos unclassified, or attempt to capture the many ‘mixed’ classes and overwhelm the discriminatory capability of the AGDS. It was made possible by a conjunction of narrow beam width 6.4° and shallow depth 1.2 to 17.5 m, which produced a sonar footprint small enough to resolve the microscale features used to define benthic groups. Survey data classified from the third-pass training DA were found to: i conform to visually apparent contours of satellite imagery, ii agree with the structural and biological delineations of a benthic habitat map BHM created from visual interpretation of IKONOS imagery and iii yield values of benthic cover that agreed closely with independent, contemporaneous video transects. The methodology was proven on a coral reef environment for which high-quality satellite imagery existed, as an example of the potential for single-beam systems to thematically map coral reefs in deep or turbid settings where optical methods are not applicable. |
| تدمد: | 1366-5901 0143-1161 |
| DOI: | 10.1080/01431161.2010.527396 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::c5fcb75e0675981479d1db38a0f25687 https://doi.org/10.1080/01431161.2010.527396 |
| رقم الانضمام: | edsair.doi...........c5fcb75e0675981479d1db38a0f25687 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13665901 01431161 |
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| DOI: | 10.1080/01431161.2010.527396 |