Digital Information Technologies and Architectures: December 2009

Wednesday 16 December 2009

3.11 References and Resources

Tuesday 8 December 2009

3.10 Information Architectures

Information Architecture relates to the organisation, labelling and navigation of information within an information system. The effective organisation of information to facilitate its efficient retrieval is becoming increasingly important as data volumes increase exponentially. This is especially relevant in the field of GIS where the vast quantities of data available mean it is imperative that only the relevant information is returned to the user to enable the swift execution of queries and drawing of maps. Geographic information stored in databases is indexed for this purpose. Grid, Qaudtree and R-tree indices all organise geographic information according to their spatial location to speed up queries and the return of information.

The labelling of geographic information takes the form of metadata, literally defined as data about data. In GIS metadata is often stored as a separate xml file containing information about a files content, quality, type, creation and spatial information such as the coordinate system. An ESRI whitepaper describes metadata as making “spatial information more useful to all types of users by making it easier to document and locate data sets” (ESRI, 2002). Thus this is another form of information architecture that facilitates the efficient organisation and effective retrieval of spatial data.

Navigation of geographic information is solved in ESRI's GIS software via their ArcCatalog architecture. Spatial data often consists of a series of files, for example a single polygon shapefile can consist of up to seven separate files including an index file, a projection file and a geometry file. ArcCatalog displays all these separate pieces of information as a single file, thus making storage, organisation and editing simpler. The application allows you to browse and find geographic information from various sources such as databases, the internet and locally; view and manage metadata; and manage datasets and datasources

3.9 Client Side Programming

My javascript application uses three functions declared in the head of the HTML document. The first, ‘newsorsport’, produces a prompt box asking the user if they are interested in news or sport and requesting they enter 1 for news or 2 for sport. The user's input is declared as a variable and converted to an integer and depending on the outcome either the function ‘area’ or ‘sporttype’ is called. Both these functions request further input from the user via a prompt box and display a link depending on the input.

I found the following aspects of creating the program particularly challenging:

Whether to put all the script in the body section of the HTML document or whether to use functions scripted in the head part and then call these in the body
The synatx of If statements. In VBA (which I have some limited experience of) 'If, Then Else' is used whereas in Javascript just the word 'If' is required
Getting the curly brackets in the correct place
Remembering to use double equals signs (==)
Getting the anchor tagged URLs to work. They need to be in the paragraph tag and the whole phrase needs to sit within double quotation marks whereas the URL is within single quotes

The fruits of all my labours (and frustrations) can be found here.

Digital Information Technologies and Architectures

Wednesday 16 December 2009

3.11 References and Resources

Tuesday 8 December 2009

3.10 Information Architectures

3.9 Client Side Programming

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