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Water Resources Database Development Process


* Analyze, evaluate, and process collected data sources

After collection, the data will be classified into the following data packages:

+ Meteorological and hydrological data.

+ Data on resources.

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+ Data on irrigation and hydropower.

Next, the map data will include digital and paper data: classify the data similarly to above. After classifying the data, we will review, update the latest data and edit and process that data.

2.1.3. Data normalization

Database normalization is a scientific method of breaking down a complex table structure into simple table structures according to certain rules that ensure no loss of data information; the result will reduce redundancy and eliminate data inconsistencies, saving storage space. Some common forms of data normalization are:

- First Normal Form (1NF): first normal form if and only if all attributes are single-valued.

- Second Normal Form (2NF): in second normal form every non-key attribute is fully dependent on the key.

- Third Normal Form (3NF): 3NF must satisfy 2NF and all non-key attributes must not transitively depend on the key attribute.

- Boyce - Codd Normal Form (BCNF): if all functions are dependent.

Database standardization requires the use of data standardization and conversion software to ensure that the data is converted to the original form when converted into the database.


and automatic conversion. The following requirements should be noted regarding the standardization of spatial object layers in digital maps:

- Standard for font encoding to enter attribute information for objects in the database: according to the Vietnamese standard encoding TCVN 6909. The TCVN 6909 standard encoding defines the Vietnamese encoding standard as a subset of the Unicode encoding.

- Spatial object relationship standards: spatial objects in the database must ensure the following principles:

+ Objects are determined from the border line and boundaries of each commune inward;

+ Do not overlap objects in the same layer;

+ No duplicate objects in the same class;

+ Land plots (land enclaves) and land-occupying objects that do not form land plots on each map must comply with the Topology law in cadastral map regulations and current land use map regulations.

- Object boundary during database standardization and integration:

+ Land plot boundary, land occupation but not creating land plot between cadastral map pieces in the same administrative unit and between adjacent administrative units;

+ Border objects with line data type (Line or linestring) such as administrative boundaries, roadways, bridges, water edges... within an administrative unit and between adjacent administrative units;

+ Map content elements of the same scale after bordering must match each other both qualitatively and quantitatively (content, stroke force, color and attributes);

+ Object attribute information must be consistent along routes within an administrative unit and between administrative units. (For example, street names).


2.2. PROCESS OF BUILDING WATER RESOURCES DATABASE

The process of building a water resources database is shown in the diagram:



Figure 2.1. Flowchart of water resources database construction process

2.2.1. Review and analyze data information content

- Review, evaluate and classify standardized and unstandardized data in detail and prepare sample data.

- Identify categories, management objects, and detailed information for


each object, relationships between objects, scanned documents and paper documents that need to be entered into the database, determining data catalog frames in the database and factors affecting database construction.

- The products are the management object catalogs and detailed information (management object catalog, detailed information for each management object, relationships and factors affecting the construction of the database).

2.2.2. Database model design

- Design data catalog and metadata models according to data standards based on review and analysis results.

- Design database model based on review and analysis results. Then enter sample data to test database model.

- The product is a database model, data catalog model, and metadata in XML format.

2.2.3. Create data for data catalog, metadata

- Create data content for data catalogs, metadata based on review, analysis and design results.

- The product is a data catalog database, metadata with full content imported.

2.2.4. Create data for the database

* Data conversion

- Purpose: to convert standardized digital data (spatial and non-spatial) into a database.

- Steps to follow:

+ For unstandardized digital spatial data, data standardization is performed according to general regulations before converting to the database (map editing, coordinate system conversion...).

+ For non-standardized digital non-spatial data:


Standardize fonts according to TCVN 6909 standard (if available).

Normalize non-spatial data according to database model design.

+ Convert standardized numeric data into a database.

- Product:

+ Numeric data before conversion.

+ Non-spatial data before normalization.

+ Database has been converted.

* Scan (capture) documents : the product is a list of scanned documents that have been attached to the layers and data tables of the managed objects.

* Enter and check data

- Purpose: Enter and check data from paper form into the designed database. Data after being entered into the database must be checked and controlled to ensure data accuracy.

- Steps to follow:

+ For paper spatial data: digitize according to specialized regulations and then perform the "data conversion" step.

+ For paper data entry (non-spatial):

Import structured data for non-spatial objects. Import structured data for spatial objects.

Import unstructured data for non-spatial objects. Import unstructured data for spatial objects.

+ Data reconciliation:

Structured data imported for non-spatial objects. Structured data imported for spatial objects.

Imported unstructured data for non-spatial objects. Imported unstructured data for spatial objects.


- Product:

+ Paper data is used for data entry (stored at the construction unit to serve the investor's inspection and acceptance when requested).

+ Reconciliation reports and issues arising during data entry.

+ The database has been fully populated.

+ Data catalog to provide, exploit and use to serve state management requirements.

2.2.5. Data editing

- Purpose: edit database according to regulations.

- Steps to follow:

+ For spatial data: Object declaration.

Corrects correlation errors of spatial data (topology).

+ For non-spatial data: content editing.

+ Present spatial data display.

- Product:

+ The database has been edited.

+ Presentation file displays spatial data.

2.2.6. Product testing

- Purpose: to check the created database to ensure completeness, accuracy and consistency with approved content.

- Steps to follow:

+ Check database model.

+ Check database content: Check spatial data.

Check non-spatial data.


+ Check data catalog, metadata.

2.3. BUILDING WATER RESOURCES DATABASE USING ARCGIS SOFTWARE

2.3.1. Database content structure

2.3.1.1. General overview of database content structure

The structure of the water resources database is designed according to the “ Geographic information framework for integrated coastal zone management” 12 and “Circular No. 16/2009 TT/BTNMT Regulations on National Technical Regulations on Environment” 13 . The content of the water resources database will focus on data types grouped into the following main groups:

- Types of hydrometeorological data include: rain, temperature, evaporation, humidity, wind, sunshine; flow, water level. All of these types of data are stored over time in time steps such as hours, days, months, years... and are created in table form. In addition, data related to the location of hydrometeorological stations such as location, existing functions... this data can be linked to digital maps.

- Water quality data type: in addition to data on the location of measuring stations, this type of data also includes other necessary data such as: salinity, silt, organic matter, nutrients, microorganisms, animal decomposition, heavy metals, minerals in water, alum, and toxic substances.

- Types of data on hydraulic works: dams, sluices, wells, canals, hydroelectric plants, pumping stations. And they are grouped by functions and tasks such as: hydroelectricity, water supply, irrigation, flood prevention, water transport, fisheries, tourism and synthesis.

2.3.1.2. General principles of water resources database

The water resources database structure model follows the following principles:


- Water resources database is a collection of structured data information about water resources arranged and organized for access, exploitation, management and regular updating by electronic means;

- Water resources database is a basic component of environmental resources database;

- The water resources database has a structure consistent with the overall structure of the environmental resources database and its component databases;

- Attribute data of water resources database is stored and displayed according to Vietnamese standard code set TCVN 6909. This standard code set defines Vietnamese encoding standard as a subset of Unicode code set.

- Water resources database is designed according to the spatial database model. ArcGIS technology of Esri (USA) is used to design, store and manage water resources database;

2.3.1.3. Scientific basis for building water resources database

The scientific basis for forming databases is according to standards. Geographic information standards are understood as a system of standards on methods, regulations on how to describe, how to represent, how to build databases from real world perception to geographic databases stored in a certain structure and format.

The geographic information standard is designed to standardize activities:

- Build geographic data according to set goals.

- Exchange and share geographic data.

- Update geographic data.

- Building application systems.

Currently, the International Organization for Standardization (ISO) has established technical committee 211 on geographic information to develop geographic information standards. In Vietnam, the Ministry of Natural Resources and Environment has

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