Preparation of Cartographic Maps for the Census of

Preparation of Cartographic Maps for the Census of Population & Housing 2011 SRI LANKA 1

The methodology of preparing cartographic maps to be used for the forthcoming Census of Population & Housing. 2

Officers entrusted with this task • All field work related to preparation of digital maps are carried out by the department’s field staff. They are assisted with ØDistrict level administrative officers. ØDivisional Secretary division (Sub district) level officers. ØLowest administrative division (Grama Niladari Division) level officers. 3

Available Maps • GN division boundary maps prepared for the last Population and Housing Census. • Sketch maps of GN divisions are prepared by overlaying, These maps on the satellite images or base maps. Note: boundary maps prepared for the last census are not accurate enough for geographic analysis but could be used to carry out census field work without any omissions or duplications. {Please see picture 1}. Field Staff are also provided with a copy of the GN division boundary maps prepared for the last census (please see picture 2). 4

Field work associated with preparation of maps • A tracing paper is pasted on the hard copy of the sketch map and field officers have been instructed to draw the GN division boundary on the tracing paper according to instructions given below. 5

Field work associated with preparation of maps – cont. Ø Following the location of Geographical feature of satellite images/ base maps, boundaries of the GN divisions should be drawn on the tracing paper. Ø If GN division boundaries do not fall with in clear geographical features such as roads, rivers etc. Ø Names of the property owners alone the boundaries should be recorded in the map. Ø Also geographical coordinates alone the unclear boundaries are taken using GPS units. 6

How Census block maps are prepared • After clearing the GN division boundaries each GN division is sub-divided in to a few census blocks, by following criteria given below Each census block should be consisted of approximately 150 housing units. As far as possible census blocks boundaries should go through clear boundaries. 7

How Census block maps are prepared – cont. At unclear census block boundaries, location of property owners together with their identification details, along the boundaries are recorded in the map. Also coordinates of a few turning points are taken by using GPS units. Census block maps are prepared for urban, rural and estate plantation sectors separately. 8

Census block maps to be used for Census field work • A separate map for each census block is prepared and pass it to the Census division to be used for listing and other census operations (please see picture 3). Digitization of the maps • All these finalized maps are digitized at the Head Office. For this, maps drawn on the tracing papers and coordinates obtained by using GPS units will be used. 9