SESSION 8: LAND SURVEY METHOD
Some years ago, to measure the land the rope or chain were used. Distance was
measured by British measurement system e.g. inch, foot, miles etc. Since 1972,
we applied metric measurement system. E.g. mm, cm. m, km. etc. In this modern
technological development, Dumpy Level system is useful for survey. Below are
listed the few basic concepts of this survey method.
Map and index lines: map is a picture of a land taken from a height. It adds to
the verbal information provided. The language, drawing, reading of the map is
standardized all over the world. The mountains, rivers, roads, the sea, lakes,
temples, fort, houses, valleys are shown in standard symbols. Therefore, any
person can read the map without knowing the script of a language.
Definition of map:
A figure of specific area seen from the top, in a proportionate scale, presentation,
symbols and signs, direction etc. drawn on a plain surface is map. Index is
shown in corner of map. Index clears the meaning of signs and symbols, direction
and scale. Index is important in map reading. Following technical things are to be
1. Proportion: the ratio of distance between two places and the distance between
two points on map is in proportion. There is correlation between actual
distance on land and the distance between two points on map. Proportion is
based on the area of landscape. E.g. if 1 cm is considered for 10,00,000 cm
then 100,000 cm is equal to 1 km. hence, 1cm is 10 km.
2. Direction: the direction is shown by the upper side arrow symbol
in the map. The upper direction is considered for the north
direction. By this sign, we can determine the other directions.
3. Signs: different signs and colours are used in a map. These are
standardized and each symbol means the same all over the
world .E.g. the narrow bridge.
4. A degree of latitude and longitude: to show a fixed place on
map, use of imaginary lines as X-axis and Y-axis is done. X-
axis presents a degree of latitude and Y- axis as a degree of longitude.
X-axis and Y-axis make fix a point on graph, likewise a degree of longitude
and a degree of latitude fix the location of a place.
Uses of map:
1. To find out the routes in new places.
2. To measure the distance between two places.
3. To find out the options of the roads.
4. To know the geographical situation.
5. To know highs and lows of a place.
6. We can also get the information of crop, weather, wind flow, rainfall, minerals,
population etc. from maps