GENERAL Project Stonehenge Survey area Sweeneys Located data type 0.1 Second Final Data Surveyed by GPX AIRBORNE PTY LTD. Job number Stonehenge Processed by GPX AIRBORNE PTY LTD. Creation date August 2007 SURVEY SPECIFICATIONS Survey flown June 2007 Traverse line spacing 75 metres Traverse line direction 000-180 degrees Tie line spacing 750 metres Tie line direction 090-270 degrees Survey height 30 metres LOCATED DATA FORMAT Variable Units Undefined From To Format Line number 9999999 1 8 I8 Easting (MGA51) metres 9999999.99 9 19 F11.2 Northing (MGA51) metres 9999999.99 20 30 F11.2 Fiducial 99999.99 31 39 F9.2 Flight number 999 40 43 I4 Direction (1=E, 2=N, 3=W, 4=S) 9 44 45 I2 Date (YYYYMMDD) 99999999 46 54 I9 Time (GPS) seconds 99999.99 55 63 F9.2 Longitude (GDA94) degrees 999.999999 64 74 F11.6 Latitude (GDA94) degrees 999.999999 75 85 F11.6 Radar altimeter metres 9999.9 86 92 F7.1 GPS altitude metres 9999.9 93 99 F7.1 Raw magnetics nT 99999.999 100 109 F10.3 Post compensated magnetics nT 99999.999 110 119 F10.3 Diurnal nT 99999.999 120 129 F10.3 Final magnetics nT 99999.999 130 139 F10.3 Pressure millibars 9999.9 140 146 F7.1 Temperature degrees C 99.9 147 151 F5.1 Raw total count cps 999999 152 158 F7.0 Raw potassium cps 9999 159 163 F5.0 Raw uranium cps 9999 164 168 F5.0 Raw thorium cps 9999 169 173 F5.0 Raw cosmic cps 99999.9 174 178 F5.0 Final total count cps 99999.99 179 187 F9.2 Final potassium cps 99999.99 188 196 F9.2 Final uranium cps 99999.99 197 205 F9.2 Final thorium cps 99999.99 206 214 F9.2 Final DTM metres 99999.9 215 222 F8.1 DATA PROCESSING COORDINATE DATA All lines are scissored to the following rules: 1) A 'smooth' edge outside the area boundary. 2) Maximum line overlap of 0 fiducials within the area boundary. The local projection is a UTM projection based on the GDA94 spheroid with a central meridian of 147 East degrees. System parallax of 0.6 fiducial has been removed. MAGNETIC DATA The magnetic data has been corrected for regional gradient by subtraction of IGRF model 2005 computed continuously over the whole area based on the GPS height. Diurnal magnetic variations have been removed. System parallax of 1.5 fiducial has been removed. Tie-line levelling has been applied. Microlevelling has been applied. A base value of 61320 nT has been added to the data. RADIOMETRIC DATA Raw channel data provided has been energy calibrated NASVD has been applied to channel data prior to windowing System parallax of 0.0 fiducial has been removed. Height attenuated to 30m AGL Airborne radon has been removed AIRCRAFT BACKGROUND UNITS Total Count 81.67 cps Potassium 23.35 cps Uranium 0.59 cps Thorium 0.67 cps COSMIC STRIPPING RATIOS Total Count 0.811201 Potassium 0.044663 Uranium 0.038646 Thorium 0.043791 COMPTON STRIPPING RATIOS alpha 0.2540 beta 0.5145 gamma 0.7997 a 0.0692 HEIGHT ATTENUATION COEFFICIENT Total Count 0.006928 per metre Potassium 0.009043 per metre Uranium 0.007186 per metre Thorium 0.006892 per metre WINDOW ENERGY LEVELS Low Energy High Energy Total Count 410.0 2810.0 keV Potassium 1370.0 1570.0 keV Uranium 1660.0 1860.0 keV Thorium 2410.0 2810.0 keV DIGITAL TERRAIN MODEL DATA DIGITAL TERRAIN MODEL CALCULATION The radar altimeter data was subtracted from the GPS heights to provide a digital elevation model which is height above the WGS84 spheroid. Using interpolation on the 120 second DMA Geoid model, a correction was computed and subtracted from the WGS84 data to convert to height above the geoid. DATA RELIABILITY This Digital Terrain Model (DTM) has been computed from data generated during the course of an airborne geophysical survey flown at a nominal spacing of 75m and data has been interpolated between such lines. Every effort has been made to make this model a useful general reference. No guarantee can be made that this model is a true representation of height above sea level as it can contain radar altimeter responses from buildings and in some instances dense timber. Users of the product should be aware of the topographic limitations mapped herewithin. Do not use this DTM for navigation purposes.