Northern Territory Coastal Waterways Geomorphic Habitat Mapping. Version 2 (1:100 000 scale digital data)

Brief description

This dataset maps the geomorphic habitat environments (facies) for 63 Northern Territory coastal waterways. This version of the dataset includes 48 newly mapped estuaries, classified as 'Near pristine'. The classification system contains 12 easily identifiable and representative environments: Barrier/back-barrier, Bedrock, Central Basin, Channel, Flood- and Ebb-tide Delta, Fluvial (bay-head) Delta, Intertidal Flats, Mangrove, Rocky Reef, Saltmarsh/Saltflat, Tidal Sand Banks (and Unassigned). These types represent habitats found across all coastal systems in Australia. Estuaries on the northern Arnhem Land, Gulf of Carpentaria coasts are predominantly tide-dominated estuaries, which vary greatly in size and floodplain characteristics.

Lineage

Maintenance and Update Frequency: irregular

Statement: Data source: Georeferenced 30 metre resolution Landsat TM 5 and Landsat ETM 7+ images. Georeferencing performed using image processing software (ER Mapper), with 10-15 ground control points per image, against 1:250 000 scale topographic maps. Aerial photographs ranging in scale from 1:10 000 to 1:80 000. Interpretation: For individual coastal waterways, the Landsat images were printed at an appropriate scale, ranging from 1:15 000 to 1:50 000. Boundaries of geomorphic habitats (facies) were mapped by hand over these printed images, with the assistance of aerial photographs and enhanced Landsat images. Where Landsat imagery was unavailable, digital images of 1:100 000 topographic maps were used. Digital capture: Hand drawn interpretations digitised on-screen over Landsat imagery, using ER Mapper software. The scale at which each coastal waterway was drawn was no greater than 1:5 000, with a window size of 650 by 650 pixels. The projection was Transverse Mercator and the datum AGD66. ER Mapper vector files converted to AutoCAD dxf files and then to ArcInfo coverages (one coverage for each coastal waterway), and polygons attributed with geomorphic habitat type. Attribution checked against the original interpretation. Logical consistency checks performed on all coverages, and the projection and datum converted to Geographic, GDA 94. Coverages merged into a single shape file, using the Geoprocessing Wizard in ArcView 3.2. Newly mapped, 48 Near Pristine estuaries were hand drawn over Landsat ETM7+ 15m resolution panchromatic band. The interpretations were scanned at 400 dpi as binary TIFF files and vectorised in microstation. Maps were attributed in microstation and converted to ARC/INFO coverages in Geographic, GDA 94. Further attribution and logical consistency checks were performed on all coverages, then merged into a single shapefile, using the Geoprocessing Wizard in ARCGIS 8.3.