Building a new city or township requires meticulous planning, and surveying forms the foundation of this process. It encompasses the evaluation and mapping of key elements such as streets, property boundaries, water and sanitary pipelines, electrical and telephone lines, and more. This article delves into the types of maps needed, the instruments used, and the process of preparing each map for successful city planning.
Types of Maps Required in City Surveying
Surveying for a city or township involves preparing several detailed maps, each serving a specific purpose in urban development:
- Topographic Map: Captures the natural features of the area, including elevations, valleys, hills, and lakes, essential for understanding the terrain.
- Street Map: Details the road network, including street names and connections between streets, crucial for navigation and infrastructure planning.
- Property Map: Establishes boundaries of public and private properties, ensuring clarity in land ownership and usage.
- Water Supply and Sanitary Map: Represents the network of underground water and sanitary pipes, facilitating the design of essential utility systems.
- Electrification Map: Shows the layout of underground and overhead electrical lines, highlighting supply points and transformers.
- Telephone Line Map: Depicts the underground telephone cables, ensuring efficient communication infrastructure.
Each map is designed to be user-friendly, enabling accurate and quick location of specific points, and is prepared by the respective departments or authorities responsible for those systems.
Instruments Used for City Surveying
Surveying requires precision, and the following instruments are essential in capturing accurate data:
- Transit Theodolite with Tripod: Measures horizontal and vertical angles with high accuracy.
- Leveling Instruments with Tripod: Determines elevation levels across the surveyed area.
- Plane Table Instruments: Provides a platform for field sketching and mapping.
- Leveling Staff: Measures differences in height for leveling purposes.
- Ranging Rods, Pegs, Optical Square, and Arrows: Aid in marking and aligning points during surveying.
- Metric Chain, Metallic Tape, and Invar Tape: Measure distances and lengths with precision.
These tools ensure that every aspect of the city’s layout is accurately recorded and reflected in the maps.
Preparation of Different Maps for a City
1. Topographic Map Preparation
The first step in topographic mapping is dividing the entire area into sectors, each enclosed by a polygon. Using a theodolite, closed traversing is conducted to establish boundaries, while plane table surveying captures interior details like roads, parks, and lakes. Key points are marked with reduced levels (RLs) using the fly leveling method, and contour surveys are conducted for valleys and hills. All sector maps are combined to create a comprehensive topographic map of the city.
2. Street Map Preparation
Street maps are prepared on a larger scale than topographic maps to include details like street names, road connections, and benchmarks for future reference. Like topographic mapping, the area is divided into parts and surveyed using plane table methods.
3. Property Map Preparation
Property maps delineate public and private property boundaries through plane table surveying. Boundaries are marked, and plots or premises are numbered for clarity. This map aids in identifying ownership and property limits in any part of the city.
4. Water Supply and Sanitary Map Preparation
Underground water and sanitary pipelines are mapped using conventional lines and symbols. Important points like inlets, outlets, manholes, and inspection chambers are highlighted. These maps are often superimposed on street maps to facilitate easy identification of utility points.
5. Electrification Map Preparation
Electrical lines, often laid underground, are represented with color-coded lines distinct from other utilities. Key elements such as supply points and transformer locations are symbolized. In areas with overhead electrical lines, poles or columns are marked on the map for reference.
6. Telephone Line Map Preparation
Similarly, telephone cables are mapped with color-coded lines and specific symbols for important points. These maps are essential for maintaining and expanding communication networks.
Integration of Maps and Collaboration with Authorities
Once all maps are prepared, they are submitted to the city’s development authority, which coordinates with relevant departments like the municipality, electricity board, and telecommunication offices. These authorities take responsibility for implementing development projects based on the prepared maps, ensuring that the city grows in a planned and efficient manner.
Conclusion
Surveying is a critical step in city and township development, providing a structured foundation for all subsequent planning and construction. The creation of detailed and accurate maps ensures that the city’s infrastructure is well-organized and sustainable. From marking streets and property boundaries to mapping utility networks, surveying sets the stage for a well-planned urban environment.