Bunce Island Terrain Model
Contents
  
Reconstructing the Past

The first of three sections of the island terrain model below illustrate topographical maps showing detail and quantitative descriptions of the entire island with the jetty and slave castle location. Non-intersecting segments called contour lines represent elevation. Contour lines develop the natural relief features of the islands terrain with closer spaced lines representing steeper terrain. Global Positioning System (GPS) is a space-based satellite system providing location and time information.

The second section, digital terrain model and wireframe comparison, was created with the information from the topographical map (topo) and CAD software. Contour lines are drawn as 2D polygons, converted to 3d polygons. This data creates a network of triangles which in turn form the terrain model. Development of the model, "smoothing" and applied "skin" appear when this image is clicked.

The final section represents a 3D perspective island wireframe and 3D rendering comparison of the island, village and slave castle. The island has a "smoothing" element applied to the normal triangular facets. Notice the village housing, jetty and slave castle, all in wireframe format. Final texture is represented when image is clicked.

GPS Data/Plotting
This contour map, from Dr. Easmon's map (1947), list height elevations for each non-interlacing contour. A scale is provided, north indicator and low water mark. In addition to the islands features of well, kilns, jetty and slave castle, the highest points of the island contain the village grave sites and Bunce House in the slave castle.

The comparative topo appears by moving the cursor over the first contour map. This image illustrates archaeologist Christopher DeCorse's topographical map of Bunce Island (2006). This recent contour plan utilized GPS data, more accurately documented the terrain and precisely located all island features. This data was the basis for constructing the computer digital model illustrated in the next island reconstruction. Move cursor on and off image
Easmon Map and DeCorse Map Comparison


Digital Terrain
This computer generated wireframe image was created by drawing each contour line from the DeCorse topo map, then changing these 2D lines to 3D polylines to establish height. The 3D polylines produce a digital terrain model with triangulated shapes forming a facetted model (not shown).

The final rendered image shown (when moving the cursor over the image) was the result of several additional steps. A draped feature removed the triangular shapes and produced a smooth accurate model of the island's terrain. Perimeter excess shape was trimmed by subtraction from the lowest contour shape yielding a final form matching the topo. A temporary neutal texture is applied to the model's skin. An added directional light creates light and shadow and illustrates the island's true form as it is observed looking straight down. Move cursor on and off image
Digital Terrain Wireframe and Rendering Comparison CAD images by Chatelain


3D Perspective Wireframe To 3D Rendering
TA perspective view of the wireframe model shows added features of village houses, chief's compound and island cemetery in the foreground. At the far end is the slave castle with all of it's internal structures. In between are jetty, well, kiln's and pavilions.

Moving the cursor over the wireframe perspective transforms it into the computer generated rendered image. Grass texture replaces the temporary neutral texture discussed in the previous reconstruction. Travelled pathways have worn away ground cover, pavilions and village houses show thatched roof texture, castle walls are stone and roof's are tile textures. Move cursor on and off image
3D Perspective Island Wireframe and 3D Rendering Comparison CAD images by Chatelain


Reconstructing the Past Slave Castle Reconstructed