{
 "currentVersion": 10.22,
 "id": 18,
 "name": "Backscatter_Images",
 "type": "Group Layer",
 "description": "Images derived from backscatter data collected while collecting multibeam sonar data.  High-resolution bathymetric data were collected from each survey area using a Kongsberg EM3002D (300 kHz) multibeam sonar system mounted in single head configuration (Figure 2.1). The multibeam sonar data were processed during the survey using Caris HIPS & SIPS v7.1 SP2 software and included: i) applying algorithms that compensated for tide and vessel pitch, roll and heave (e.g. elevation errors caused by dynamic draft of the vessel); ii) using sound velocity profiles (collected while underway and at several stations in each survey area) to correct for variations in the speed of sound through the water column, and; iii) software filters and visual inspection of each swath line to remove any remaining artefacts and noisy data (e.g. nadir noise and data outliers)\nTidal corrections were also applied to bathymetric data, based on a co-tidal solution. This solution is derived from the average tidal amplitude at multiple tide stations weighted inversely to the distance between the tide station and the point of interest. For each survey area, a tidal zone was defined by a closed polygon and included a primary tide station of known location and two or more secondary tide stations. Predicted tides were then generated using tidal constituents requested from the National Tidal Centre within the Bureau of Meteorology for these predefined tide stations. A Zone Definition File (.zdf) for defining the zone, the primary and secondary tide stations, and the associated predicted tides was created and used in Caris HIPS & SIPS V7.1 SP2. The final surface grid (bathymetric map) was then produced to ≤10 cm vertical resolution and 2 m horizontal resolution (cell size of the surface grid).\nFor more information see:\nhttp://www.ga.gov.au/metadata-gateway/metadata/record/76658",
 "geometryType": null,
 "copyrightText": "© Commonwealth of Australia (Geoscience Australia) 2016. This product is released under the Creative Commons Attribution 4.0 International Licence. http://creativecommons.org/licenses/by/4.0/legalcode",
 "parentLayer": {
  "id": 7,
  "name": "Bathymetry_Products"
 },
 "subLayers": [
  {
   "id": 19,
   "name": "backscatter_grid_1"
  },
  {
   "id": 20,
   "name": "backscatter_grid_2"
  },
  {
   "id": 21,
   "name": "backscatter_grid_3"
  },
  {
   "id": 22,
   "name": "backscatter_grid_4"
  }
 ],
 "minScale": 0,
 "maxScale": 0,
 "defaultVisibility": true,
 "extent": {
  "xmin": 270598,
  "ymin": 8648288,
  "xmax": 333336,
  "ymax": 8748726,
  "spatialReference": {
   "wkid": 32752,
   "latestWkid": 32752
  }
 },
 "hasAttachments": false,
 "htmlPopupType": "esriServerHTMLPopupTypeNone",
 "displayField": "",
 "typeIdField": null,
 "fields": null,
 "relationships": [],
 "canModifyLayer": false,
 "canScaleSymbols": false,
 "hasLabels": false,
 "capabilities": "Map,Query",
 "supportsStatistics": false,
 "supportsAdvancedQueries": false,
 "supportedQueryFormats": "JSON, AMF",
 "ownershipBasedAccessControlForFeatures": {"allowOthersToQuery": true},
 "useStandardizedQueries": true
}