ExampleCity_axial_viewpoints

<p dir="ltr">This dataset contains the representative viewpoints and visibility-based axial maps generated for six districts — Amsterdam, Barcelona, New York, Paris, Shenzhen, and Tokyo — by the two-stage visibility framework described in:</p><p dir="ltr">From three-dimensional isovists to axial maps: A unified framework for visibility-based urban representation.</p><p dir="ltr">How the data were generated</p><p dir="ltr">Each study area (approximately 2–4 km², bounded by major roads) was represented by building footprints, building heights, and the scene boundary.

Candidate viewpoints were generated in the navigable open space by constrained Delaunay triangulation. A minimum set of representative viewpoints was then selected by solving a set-cover integer linear program (Gurobi) over a GPU ray-traced visibility matrix, requiring complete coverage of uniformly sampled ground and facade target points (eye height 1.70 m, vertical field of view 60°). From the selected viewpoints, radial sight lines were extracted and local length maxima taken as candidate axial lines, which were clustered by angular similarity, spatial overlap, and viewpoint intervisibility, and then pruned to the final compact axial map.</p><p dir="ltr">Contents</p><p dir="ltr">- Viewpoints — the selected representative viewpoints for each city (one ESRI shapefile family per city: .shp, .dbf, .shx, .prj, .cpg, .shp.xml).</p><p dir="ltr">- Axial — the generated visibility-based axial lines for each city (same shapefile structure).</p><p dir="ltr">Filenames follow the pattern _viewpoints and _axial. </p>