1.1.3. Data Quality

There are several reasons why one develops a multimedia application. You might be contracted by a customer or you just want to develop a multimedia application for fun during your spare time.
Sometimes when getting the request of developing a multimedia application, the employer already possesses some data which has to be included in the application. If so, it is important to view the data at an early stage, because often, the data is not prepared for this specific project. The files may have the wrong format or the geometry data is often too detailed for a map that has to be displayed on a screen, etc.

Have a look at the following example which illustrates a file whose data is not generalised and a file whose data is generalised.

Not generalised data

Generalised data

Not only the level of detail is an important attribute when viewing the data but rather the quality of data in general.

According to (Hurni 2005), the data quality depends on the following attributes:

• Precision (Positioning Accuracy depending on original measurement data, Updating, Generalisation and Reproduction Technique)
• Up-to-dateness
• Completeness
• Correctness: data should be error-free
• Reliability respectively Plausibility
• Readability, Data Format
• History (Resources, Data Collection, Transformations)

It is important to view as soon as possible the received data and check it for the listed items. Often the data is either not usable or a lot of time has to be spent to prepare the data for the project. Estimating the time that may have to be spent to prepare the data for the project is an important part of the issue analysis.
If you would have to spend most of your available time for the data preparation, you have to doubt the feasibility of the project.

Often, you will not receive any data for your project and you will have to look for data in various sources. That is why the next chapter deals with data sources.