Spatial data sets in hydrology project
The manual provides an overview of spatial data sets: selected themes, input data, output data and generation methodology, and the spatial database organization (including map tiles and TIC mark Ids) and data specifications in regard to scale, map projection, digitization accuracy, and registration accuracy between layers. Theme-wise chapters cover the classification scheme, input data specifications, methodology flowchart, feature coding standards, output file naming convention, internal QC and external QA, and specifications for deliverable products.
Annexures of the manual describe how the classification and map accuracy is estimated, the standard procedure for digitization, the internal quality control and external quality audit procedure, and provide details of the report accompanying each digital map tile including the QC/QA statement (map tile code, generation date, mapping accuracy, thematic accuracy, and digitization accuracy); brief description of input data, generation procedure, and output products; and contact address in vendors office for future follow-up.
Procedure for Generating Data Sets
The Ground Water department of each participating State will be responsible for generating data sets within the State. The data sets will be produced through outsourcing to vendors through a competitive bidding procedure.
A State Level Technical Committee consisting of representatives from the State surface and ground water agencies, Central Water Commission and Central Ground Water Board will support the State GWD. It is recommended to include the Geological Survey of India (GSI) for i) technical inputs on geology related themes and ii) to facilitate procurement of data sets from the National Geoscientific Data Centre developed under GSI-BRGM Project. The Technical Committee will provide guidance and support on defining fresh spatial data generation, external independent quality audit of data products and integration of spatial data sets into the State Surface and Groundwater Data Centres.
The HLTG will oversee all the generic aspects such as selection of minimum GIS data sets, standard methodology to be followed, bidding procedure including vendor qualification by appropriate weighting, and integration of GIS data sets into the State and National Data Centres.
Preparation of Bid Document
A generic bid document will be prepared by the Consultants, and approved by HLTG for adoption by the State GWDs. The bid document will specify data generation requirements, methodology to be followed and qualification of vendors as part of the evaluation procedure. Particularly important is the qualification of vendors by assigning weights to financial strength (annual turnover) to undertake the large job, years of experience in the mapping and digitization activity, experience in multi-theme mapping in the same region, adequate computer hardware and software, supporting facilities such as soil lab, trained manpower (academically qualified, previous experience in thematic mapping) and certification of successful completion of past work. Selection of qualified vendors by weighting is essential in view of past experience where unqualified vendors were selected based on lowest quotation, and work was not completed successfully.
Bids will be invited for a ‘minimum lot’ of data sets (perhaps regional coverage of all themes which is cost effective from field visit angle, and ensures internal consistency between themes and theme matching across map sheets). The proposed internal QC procedure (at different stages of data set preparation) needs to be detailed by the bidder.
Joint Ventures between bidding companies (with the responsibilities of each agency to be listed) will be encouraged so that the whole State or a large region within the State is covered by one such group. The bid would include penalty clauses for delayed delivery and poor map quality.
Bid Evaluation and Issue of Order
The responses received from vendors will be evaluated as per the weighting procedure defined in the bid document, and the successful bidder will be identified for issue of order.
External Quality Audit and Acceptance of data sets from vendor
Generation of standard and consistent data sets by multiple vendors in different locations requires that rigorous quality control is exercised internally and through independent external audit. Internal Quality Assurance procedures will cover different critical stages in data set generation, starting from appropriate satellite and other map input data selection, thematic interpretation and validation, and final map validation. The stages in the digitization process will cover scanning and digitization, labeling and attribute tables, and product labeling and reporting. Quality assessment will involve both visual inspection and measurements. The vendor will develop a comprehensive QA procedure and report compliance. In addition to the internal QC of the selected vendor generating the data set, an independent quality audit by the State GWD is proposed at specific stages of data set generation. While internal QA will cover each data product, external QA will be on sampling basis.
A checklist of parameters to be assessed at each stage will be prepared and completed and attached to the report accompanying the product. For example, the data selection assessment will involve the parameters of year and seasons of satellite data, sensor, and area coverage corresponding to specified SOI map.
The QC report will also be accessible to the external QA team during visits to the vendor site. The products delivered by the contract agency will be accepted by the State GWD when they satisfy the criteria defined in the bid document.
Integration of Spatial Data Sets in the Data Centres
The State GWD will be responsible for the integration of spatial data sets in the State Ground Water Data Centre, and for providing a copy of the data sets to the State surface water agency, which in turn will be responsible for integration in the State Surface Water Data Centre.
The State GWDs will also provide a copy of data sets to the Central Water Commission and Central Ground Water Board, for integration in the respective National Data Centres.
Conclusions
The generation and
integration of spatial data sets in the national and State Data Centres will
provide the spatial dimension to the point measurements made under the Hydrology
Project. Considering the importance of these data centres all care need to be
taken to generate authentic, reliable and accurate data. Any inclusion of
existing data shall be only when the data specifications are satisfied, and
fresh generation shall ensure the highest data quality.