Flat Incline offers an alternative representation of terrain in Washington Heights. Distinct from topographic contours — which describe a continuous line of height — here, a similar domain of height is described by variable square areas.
In reading the unfamiliar view, one asks:
- How does built form change with respect to terrain?
- Where should terrain be measured from in a building, the basement or the roof?
- What areas are flat and which are isolated by steepness?
Zoom, and thus scale, has been restricted. However, users can pan, and a slight change in extent changes which pixels fall into which evaluation areas. As a result, panning changes whether an area is considered steep or flat, and forces a re-evaulation of the questions above.
A slider toggles what parts of the original RGB image are seen, clipping to subdivisions of a particular size.
Technical
Pixels from a rendered Digital Elevation Model are evaluated to find the height differential for an area. If the difference is greater than a given threshold, the evaluation area is subdivided and each subdivision is re-evaluated. This process continues until the height differential of all following subdivisions is lower than the threshold or a minimum evaluation area has been reached. The result is a grid of squares, in which smaller areas indicate steeper terrain while larger squares are relatively flat.
NB: The top surface of built form is included in calculation of height-change over an area.
Next Steps
- Similar study, but where the threshold is configurable with a slider.
- Allow users to select an area on hover, instead of with a slider.
- To improve the illusion of performance, draw the subdivision incrementally to the screen as they complete (refer to Dan Shiffman’s recursion tutorials)