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This report summarises work undertaken to provide ground control for digital terrain models(DTMs) of the Quindabellup and Wambellup sub-catchments. The DTMs will be generated using digital photogrammetry; the ground control was obtained using differential Global Positioning System (D.GPS). Description of Bench Marks (BMs) and summary sheets of Standard Survey Marks (SSMs) located in the general area, were obtained from the Department of Land Administration(DOLA). A ground survey was carried out to confirm the location and condition of BMs and SSMs in the two sub-catchments. Five SSMs were selected as reference points for the D.GPS survey. A further 8 bench marks and 1 SSM were identified for vertical control. Photo preparation included identifying sites for control observations. These sites were visited in the field and a feature that was clearly identifiable in the air photo and on the ground was selected and used for the GPS observation. Bench Mark elevations were transferred to the centre line of the adjacent road. The D.GPS survey was carried out using a Trimble 4000 SSE dual frequency receiver as a base station and either a 4000 SSE or 4000 ST (single frequence) as a roving receiver. Both receives were used in 'static' mode with observation times not less than 50 minutes.


Catchment, Digital Terrain Models, Global Positioning System