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trol positions and to strengthen each map assembly by incorporat ing templates and astro 
ixes from adjacent maps, (Each individual mar sheet covers 15 degrees along the paral- 
lel ard 1 degree along the meridians) 
Where additional scale and/or azimuth data is available from geodetic, engineer- 
ing or cadastral surveys, it is customary to use this for local block control and allow 
the block to be adjusted as an entity into the rest of the assembly. 
In the course of ground surveys, when moving from one astro fix position to 
another, spot elevations are taken with aircraft type pressure altimeters and subsequently 
corrected on the basis of the regular readings taken at surrounding meteorologicel stations. 
During aerial verification surveys additional spot elevations are determined by 
flying close to and level with mountain tops and by flying close to the ground in flatter 
terrain, (This latter procedure is in the course of being replaced by a technique of 
combined radar altimeter and pressure altimeter readings) 
The object of heighting operations at this stage is to obtain enough spot ele- 
vations to permit interpolation of contours for I,C,A.0, 1:1,000,000 scale charting, 
A limited amount of planimetric mapping has been contoured and produced as a 
tandard topographical map showing 250 feet contours at a scale of 12253 140, (Recently 
decision has been made that all future maps will be at a scale of 1:250,000). Con- 
ouring under these circumstances has been obtained by estimation on the stereoscopic over- 
ap controlled by field barometric elevation and in some instances from simple parallax 
ceacurement which are then transferred to the compilation plot, 
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Another activity of the Division is the mapping of Antarctic Territory, Originally 
the basic maps of this area were plotted from the findings of early explorers, In 1954 
topo surveys were carried out by the Australian National Antarctic Research Expedition, 
and field surveys in this area have continued since then, Air photography taken with an 
RC9 or K17 (in Trimetrogon form) is flown in Beaver or DC3 aircraft by an Antarctic Flight 
of the Royal Australian Air Force, This photography is controlled by astro or solar fix 
plus intersection of topographical features by theodolite or terrestrial photography, 
   
   
To aid in the photo identification of the ground control points a Polaroid Land 
Camera is used, This camera has the developer incorporated with the film and provides 
an immediate print, without dark room facilities, Before landing, the surveyor photographs 
the feature and surrounding terrain from the air and is thus able to make an identification 
of the astro fix before leaving the area, 
    
   
  
    
Maps at various seales of 1:500,000 and 1:2,000,000 have then been plotted by 
graphieal methods to show the pionimeteic detail and such spot heights as dctermined by 
ground parties or from.a combination of airborne pressure altimeters and radar altimeter 
readings, 
Royal Australian Survey Corps 
  
Besides having a commitment to assist in Commonwealth mapping as requested by 
         
other governmental departments the Royal Australian Survey Corps has the responsibility 
of supplying the Australie: EN with aerial photog a. mapping and photo maps in any 
area as required by the Staff. Briefly, the yal Australian Survey Corps is 
currently carrying out in most states of the do eve th, its organisation being 
such that each Military ! has rvey and map compilation element to satisfy the 
mapping requirements of sn command vh they are attached, This element is able to 
obtain control and plot from air photographs with 7 and 3 projector Williamson-Ross Multi- 
plex Eguipment up to the compilation stage. Compilations are then farwarded to a central 
unit where facilities exist for fair drawing,photography and the lithographic reproduction 
of the multi-coloured map. 
  
Prior:to 1955 the Corps carried QUK topographical mapping at the seales of 
1:63,360 and 1:253,440 which scales were also used BY other civilian mapping organisations, 
It has now been decided to adopt the reni. ‘scale for all future army mapping and since 
1955 maps have been produced at 1:50,000 with 50 ft, contour interval and 1:250,000 with 
250 ft eontour interval. A small amount of mapping at 1:25,000 with 25 ft. contour 
interval is also carried out mainly for use in areas where military training takes place 
Williamson-Ross Multiplex is the only photogrammetric plotting equipment used 
cy the Corps and its use is standard procedure for mapping published at the scales of 
1:25,000: and 1:50,000. In some instances this equipment has also been used for 1:250,000 
mapping but owing to the existing photography (mainiy K17 at seale of 1:140,000 and larger) 
this is considered uneconomical and a common method at this scale is to assemble the photo- 
graphs by slotted template within ground control, Detail is plotted by simple graphical 
methods assisted by Walch Sketchmasters, When required 250 ft contours are obtained by 
stereoscopic interpolation between control heights supplemented where necessary by parallax 
measurements, 
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