Lake catchments on Broknes, Larsemann Hills

Full description

Catchment boundaries of the the lakes on Broknes, Larsemann Hills.
These catchments were generated using the FLOWDIRECTION and BASINS routines in the GRID module of ArcInfo GIS.

Lineage

Progress Code: completed

Statement: Data Quality ------------ Positional Accuracy 1 m to 10 m Attribute Accuracy High Logical Consistency Full Completeness Full Lineage -------- Definition of lake boundaries is a multi-stage process which can be summarised as follows: * acquire contour data * build digital elevation model (DEM) * generate flow direction model * generate lake drainage model The contour data were acquired from aerial photography flown in the austral summer of 1994-5 using a Zeiss UMK metric camera with a lens focal length of 100 mm. It was flown at a height of 1000 metres and is at a scale of 1:10,000. The DEM was generated using the TOPOGRID cell-based modelling routine in Arc/Info GIS version 7.1.2. A cell size of 5 metres was found to give the best delineation of drainage basins. Flow direction was determined using the FLOWDIRECTION routine in Arc/Info GRID. This determines the flow direction from each cell to its nearest downslope neighbour. Drainage basins were determined using the BASIN routine in Arc/Info GRID. The resulting gridded data were then converted to a polygon (vector) coverage of the catchment boundaries using the GRIDPOLY routine. Those drainage basins that included a lake were selected and built as polygons. Minor edits were made to the catchment boundaries to clean up residual polygons formed by individual grid cells. The derived catchment boundaries were manually checked against the original contour data to ensure they conformed to the apparent watersheds. The automated procedure had most difficulty around the edges of the DEM particularly along the coastline and edge of the ice cap. Attribute Metadata ------------------ Table Name BROKLKBN.AAT Item Name FEATURE Item Definition 24,24,C,0 Description Description of the feature - in this case lake catchment boundaries Table Name BROKLKBN.AAT Item Name BROKLKBN-ID Item Definition 4,5,B,0 Description Unique feature identifier Table Name BROKLKBN.PAT Item Name LAKE_NAME Item Definition 24,24,C,0 Description Name of the lake within the catchment. Names taken from 1: 25000 map (pub. 1991) Table Name BROKLKBN.PAT Item Name LAKE_NO Item Definition 6,6,C,0 Description Lake number as ascribed in ANARE Research Notes 74 - An atlas of the lakes of the Larsemann Hills Table Name BROKLKBN.PAT Item Name FEATURE Item Definition 20,20,C,0 Description Descrition of the feature - in this case lake catchments Table Name BROKLKBN.PAT Item Name BROKLKBN-ID Item Definition 4,5,B,0 Description Unique feature identifier Table Name BROKLKBN.PAT Item Name GRID-CODE Item Definition 4,8,B,0 Description Code generated by ArcInfo GRID - retained when converted from a gridded dataset to polygons