CS) Informative Maps on PDA-phones
Chui Pui Ling Page 9
Early days, mapping of urban Hong Kong and Kowloon was at 1:600 scale and New Territories area was mapped at a scale of 1:1200 with neither information of height nor contour. With realization in the early son the essential needs for accurate large-scale maps with contours for planning and development, a project with aerial survey was carried out for about 10 years. The project provided mapping at 1:60 scale,
with foot contours, covering Hong Kong Island, Kowloon and New Kowloon but the hilly areas and outlying islands of the New Territories were covered at 1:1200 scales with foot contours [6]. Inline with the
metrication policy in the s, the imperial grid was converted to metric unit of measure in 1975-1977. A resurvey was carried out into improve the consistence and accuracy and anew geodetic datum, HK80 Geodetic Datum using International Hayford (1910) as the reference ellipsoid and the same projection origin was adopted (Figure 2 [7]). Today, digital mapping at various scales from photographs and the terrain data are available
for engineering design, earthwork calculation and topographic mapping.
Grid System Hong Kong 1980 Grid System (HK 1980 Grid)
Projection Transverse Mercator
Geodetic Datum HK80
Reference Ellipsoid International Hayford (1910)
Origin of Projection Old Trig 2 “Patridge Hill Latitude 22 18’ 43.68” N Longitude 114 10’42.80” E
Grid Coordinate of Origin 819069.80 mN
36694.05 mE
Scale Factor Unity (1.0) along the central meridian at old Trig 2
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