|Duration of assignment (months):
|Name of Client: Japan Development Institute (JDI)|
|Contact Person: Dr. Shoichi Kobayashi
|Start date (month/year): January 2019
Completion date (month/year): July 2019
|Narrative description of Project:
NewVision’s appointed engineers/experts assisted JDI with topographic and bathymetric surveying. NVSL staff carry-out RTK based Topographic and Bathymetric survey at the site. Based on the information provided by BEZA, the boundary line of the zone area to be confirmed and demarcated. Topographic and Bathymetric Map to be prepared using the collected survey data. Alignment and position of buildings, Road, Ponds (major ones), and Structures will be demarcated using the satellite image and ArcGIS mapping. The grid spacing of 10m x 10m was used in the output topographic maps. NVSL also prepared a high-resolution Digital Elevation Model (DEM) using the ArcGIS Spatial Analyst system for the proposed project site including contour line generation at an interval of 5 m. To conduct detail cartographical mapping (on the GIS platform) of surveyed data, elevation models (DEM) with existing land use, water bodies, and so on at a scale of 1:5000 was used.
Scope of Work for Topographic Survey:
The scope of work for the topographic survey of Plot 23 of Mirsharai Economic Zone included:
a) Obtaining relevant survey data and maps;
b) Field Work;
a. Boundary Confirmation;
b. Existing manmade and natural ground features;
c) Map Production;
Scope of Work for Bathymetric Survey:
The scope of work for the bathymetric survey of Plot 23 of Mirsharai Economic Zone included:
1. Project planning and survey design;
2. Data and information collection;
3. Data analysis and report writing;
4. Topographic & Bathymetric drawing & mapping using Arc-GIS & AutoCAD;
|Description of technical specialization provided by the firm:
The NVSL and Esolve staff worked in collaboration in survey work. The coordination and leading position were held by NVSL’s staff where the Esolve experts guide the NVSL staff in different critical issue analysis.
The RTK based topographic team was deployed and fully supervised by the NVSL’s staff and day to day update and data checking was conducted as well. After getting the raw data from the field survey team, they were taken in digital format and clear the vogue data. After the pre-processing and post-processing of the dataset, they were mapped in ArcGIS 10.3 paid version software. Using the data, a moderate resolution Digital Elevation Model was prepared by the NVSL GIS experts and the output were presented in a standard mapping system.
The bathymetric survey was carried out in the sea part of the Bay of Bengal covering an area of about 2.0 km x 500 m. DGPS and Echo sounder was used in the bathymetric survey. A pre-set transect line was set where the survey would be carried out. These lines were configured in the HydroPro Software. During the survey, the boat (carrying survey equipment) was placed along the desired line with the help of data from DGPS on the helmsman monitor. The water depth was measured by a digital echo sounder. The data from the echo sounder and DGPS were integrated by a computer through HydroPro survey software. The water level was also recorded relative to the datum (MSL) by staff gauges (with a known gauge zero value) near the Bathy area. The depth level was visually inspected in the computer using HydroPro software. The depth reading was checked manually using a staff lowered from the side of the boat. The digital data was then processed to remove spikes or erroneous data using HydroPro software. The depth data was converted to a local datum (elevation in MSL) using synchronous water level data (from the fixed staff gauges) and exported in the ASCII file format. The dry area along the transects was surveyed by the conventional survey (fly levelling) and Total Station survey. Total Station was used in acquiring land levels along with positioning (UTM Coordinates) in bank slopes and beach area. In this connection, several control Points (x,y,z) were established on the site. The position (x,y) of the control points were established by DGPS and the elevation (z) was obtained through fly levelling.