Blue Mountains Revealed: Prototype Production

Following on from exploring the layer combinations, described in the previous post, some final changes were made to the base raster from which the map tiles will be split. Firstly, to facilitate geo-referencing the base grid, an equal vertical and horizontal grid offset was applied at the rendering stage. This produces a map-like view that has the vertical aspect enhanced through the Linear Framework. Secondly, a reduced tonal range was used for the hypsometric tinting; this improves the clarity of the lower elevations, however this needs further work so as to enhance the contrast. The size of the resulting raster for the dataset area was 9055 × 13224 pixels.

The image was geo-referenced using gdal_translate to create a GeoTiff which was imported into MapBox’s TileMill to create an MBTiles SQLite file. This file was then expanded using mbutil to create a directory structure of tiles to be rendered through a client-side mapping library, in the prototype instance, Leaflet was chosen. It should be noted that no generalised elevation datasets were used to create the smaller scale zoom levels. In the case of this prototype, the down-sampling of TileMill is the only process applied. An investigation into generalisation across zoom levels would improve clarity and user experience. The image below links to the prototype map interface, this is not optimally hosted, so some of the tiles may take a few moments to resolve as you move through the zoom levels. This version is purely concerned with terrain browsing, subsequently, no linkage to cultural land-use or human settlement/constructed features is made.

Map Interface
Map Interface: Click to Open