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

2. Contents
Introduction Datamodel The use of GIS maps Data storage

3. Introduction

4. 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

5. 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

6. 2. Data model

7. 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

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

9. 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

10. Importing autocad drawings
Data model

11. Data-sets and layers
Data model

12. Identify Data Attributes
Per attribute or layer
Data model

13. 3. The use of GIS maps

14. 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

15. 4. Data storage

16. 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