SURVEY DEPARTMENT TO DEMONSTRATE MAP-MAKING

Press, Volume XCV, Issue 28284, 23 May 1957, Page 14

SURVEY DEPARTMENT TO DEMONSTRATE MAP-MAKING

The step-by-step story of the birth of a map will be told by the Lands and Survey Department in a 65ft display at the map exhibition to be held by the Canterbury branch of the New Zealand Geographical Society from June 4 to 7. ’ Commencing with the basic problem of the cartographer—the representation on a plane surface of a portion of the curved surface of the earth—the display will show the part played by the surveyor who selects the control stations throughout the country and connects these stations with a network of triangles which forms the foundation on which all mapping is based. Then will be shown the work of the computers, the “back room boys,” who supply data to position such things as the graticule, or network of latitude and longitude lines, on the map. The layman, the map user, is frequently quite unaware of the essential part they play. In modern topographical mapping, the -use of aerial photographs is universal. The aeroplanes and cameras to produce the photographs, and the elaborate and expensive equipment used to translate the details for map making will also be illustrated. The specialists who add to the map all the detail from the aerial photographs are called photogrammetrists, and the result of their work will be displayed in the form of a master sheet in colour linework.

At this stage, the map passes to the cartographers, the skilled penmen who produce the fair drawings for the printer. Each colour requires a separate drawing on a stable plastic material to ensure accurate registration in the printing process. Associated with these fair drawings are progressive pulls from the printing press. The production of a map as team work

demanding the co-ordination of specialists is the theme of the display- w Topographical maps, as an essential feature for military operations, first came into prominence at the time of Napoleon, although one of the earliest was a Sumerian map of the known world, on clay tablets, made to illustrate the military operations of Sargon of Akkad (B.C. 2700). Since the time of the Pharaohs, man has used land-holding maps, usually for tax-gathering purposes. but civil authorities generally overlooked the value of topographical maps in planning. These are now recognised in the development of the resources of a country, large or small. The aerial photograph, with the associated survey and compilation techniques, now permit economical mapping.