Technology and Design

DOHA utilises web technology which allows integration of services and data from complementary sources as a mashup. Mashup combines different technologies and disperse data to produce a new enriched product (Min et al, 2008). The mashup application is user-centred and user-driven (Maness, 2006).

DOHA was design using open source software which allows flexibility as well as independence from proprietary software (Anderson and Moreno-Sanchez, 2003).

Architecture

DOHA was implemented using Leafelt, an JavaScript lightweight library for web mapping. Leaflet is "designed with simplicity, performance and usability in mind" and is being used by sites such as Flickr or Pinterest.

The use of Leaflet as the client side technology proved to have several advantages. Wide range of plugins developed by third parties provide a quick and flexible way to implement required functionality.

The server side of the application was built using only server storage space where static vector and and raster files are stored. This implementation does not require additional GIS server software or server-side scripting languages to be installed. The data are handled and by the mapping library and are loaded asynchronously to avoid reloading the page. DOHA employes Open Standard formats: Tile Map Service (TMS) and GeoJSON.

Map Tiles ala Google Maps or "slippy tiles"

Tile Map Service (TMS) is a specifiction for raster tiled web maps. Web tiles are usually pre-rendered raster images. It is one of the fastest methods of publishing the maps through internet because only tiles for current display area are being transported through network. These tiles create a “zoom pyramid” where the number of tiles changes according to the current zoom level. One raster tile usually has a resolution of 256 x 256 pixels and available in PNG or JPEG formats. The tiles may be published using server software but the minimum requirement is a disk space.

Web Cartography

Web Maps representing Doha's urban development were produced using map design software called TileMill. TileMill can render web tiles as well as apply visual effects by using CartoCSS stylesheet language.

The design resembling vintage maps is inspired by work of Scottish map engravers, printers and publishers, John Bartholomew & Son Ltd.