QGIS, the data model, use and storage Introduction to GIS QGIS, the data model, use and storage

Contents Introduction Datamodel The use of GIS maps Data storage

Introduction

Introduction A GIS (Geographic Information System) is a collection of tools for collecting, storing and displaying spatial data from the environment around us. It allows you to create, visualize, query and analyze geospatial data by producing maps and geospatial analysis. In a water supply system, GIS can support management decisions by providing information for: Asset management and damage prevention Network planning Introduction

QGIS Quantum GIS (QGIS) is a user friendly Open Source GIS. QGIS supports vector, raster, and database formats. The major features include: View and overlay vector and raster data in different formats and projections without conversion to an internal or common format Create maps and interactively explore spatial data with a user friendly graphical interface, including publishing maps on the internet Create, edit and export spatial data Perform spatial analysis and adapt QGIS to your special needs through extensible plugin architecture Introduction

2. Data model

Data collection To be able to visualize assets on a map, they should be represented in the database including their exact spatial coordinates The location of assets can be determined with GPS devices that can measure and record specific locations within a coordinate reference system There are different coordinate reference systems: all define specific map projections and include transformations between the different systems Data model

Attributes, codes and symbols All network attributes (hydrants, chambers, valves, etc.), must have a unique serial number (code) and a corresponding symbol Data model

Water supply network The pipes of the network are divided into three types of network: Transport network – the network between the production unit and a reservoir. There are no service connections attached to this network Distribution network – the distribution network divides the water into the supply areas. To this network the service connections are connected; House connection – The pipes that connect the customer to the distribution network. These pipes are the last points of a network In GIS, different data-sets are represented in different layers that can be turned on or off in map representations to serve different purposes. As such, the three differnet types of pipes can be viewed separately as well as a complete network Pictures? Data model

Importing autocad drawings Data model

Data-sets and layers Data model

Identify Data Attributes Per attribute or layer Data model

3. The use of GIS maps

Management Information It is possible to use the source data in QGIS to make weekly, monthly and annual reports for management. Reports can support managers and team leaders to make decisions on network and maintenance planning. Reports could cover: The network, including (planned) changes Assets, including failures (such as pipe burst and leakages and broken valves and meters) and (planned) maintenance For NRW reduction activities, GIS maps are essential for identifying and designing DMAs Data model

4. Data storage

Data Storage and management To save the original data it is important that QGIS is running on one computer that stores the sources files of QGIS. To prevent data loss it is recommended to make a daily backup of the all the files and copy these files to a server. Use of a server to access the GIS on different computers? For GIS to work it is key to keep the database up to date: make sure that any changes in network or assets are uploaded Data model