A project on township or city surveying involves proper coordination of all types of development work necessary for the township or city. It entails implementation of the following systems:
- Street system
- Property lines
- Water supply system
- Sanitary system
- Electrification system
- Telephone system
In the case of a newly developing township or the modification of one in existence for some time, a plan for development should be clearly worked out so that the facilities provided in the master plan may be suitably extended.
Instruments Required for Conducting City Survey
The following instruments are required for conducting a city survey:
- Total station with stand
- Leveling instrument with stand
- Leveling staff
- Metallic tape
- Invar tape
Preparation of Topographic Map
The entire area is divided into a number of sectors, each of which is enclosed by a polygon. The polygons are connected by common sides. They are treated as closed traverse and the traversing is done by total station. The interior details are located by plane table or the transit-and tape-method. These details include houses, roads, lakes, parks, railway lines, stations etc.
Fly leveling is undertaken to establish the RLs of important points and benchmarks. Contouring is done by plane table or tachometer. The nature of the ground surface is indicated in relief (coloring, shading, hachuring, etc.) in the map.
Finally, all the sectors are assembled in one map so that the township area or city area.
Preparation of Street Map
The street map is prepared using a large scale to show distinctly the network of streets, roads, lanes, parks, etc. Names of streets, roads and parks should be mentioned. In this case also the township area is divided into different sectors. The street map of each sector is prepared by plane table. In such a map the location of interior details (lakes, houses, and other properties) need not be shown. Fly leveling is done along the streets and benchmarks are established at different points for future reference.
Preparation of Property Map
This map is also prepared using a large scale to show the boundaries of public and private properties, plot numbers, premises numbers, and so on. The property map is also prepared by plane table by dividing the total township area into different sectors.
Preparation of Water Supply and Sanitary Map
The network of the water supply distribution system and that of sewer lines are laid underground. So, to facilitate location of any spot from top, the entire networks of the water supply and sanitary works are shown by conventional lines on the street survey map. All the essential lines and points (such as intake points, purification point, check valves, fire hydrants, manholes, loopholes, inspection chambers, etc,) are marked with specific.
Preparation of Electrification Map
Generally, the network of cables for electrification of the township or city is also laid underground. Therefore, the methods of distribution should be marked on the street survey map using a different color convention or by suitable symbols. The specific points of the supply line should be clearly marked to aid easy location of any spot in case of cable fault. The network of the supply system should be indicated on the street survey map even if the electrification is through overhead lines.
Preparation of Telephone Map
The network of telephone cables also lies under the ground. So, to aid location of a fault, the network system is shown on the street survey map using a certain color convention or by suitable symbols.
The development authority of the city or town is responsible for the construction of streets, roads, culverts, bridges, flyovers, bypasses, subways, parks, public places, etc. The sanitary and water supply system is implemented by the municipality or corporation. The electrification program is carried out by the state electricity board, and the telecommunication system is run by the telegraph department.