Quadtree Search

Quadtree Search

This example visualizes a quadtree spatial index by rendering its hierarchical rectangular cells as SVG rectangles. As the mouse moves, it searches the quadtree for the nearest of 2,500 randomly generated points, highlighting the closest point in red. The visualization uses the d3.quadtree API to build and search the index, with d3.select and d3.mouse handling mouse events. The quadtree’s cells are drawn via the visit method, while points are displayed as SVG circles.

91% match

Quadtree - nearest neighbor

Clicking on the diagram places a yellow query point and a quadtree nearest-neighbor search identifies its closest orange base point, highlighted red. The d3.geom.quadtree recursively visits green rectangles, with color saturation indicating depth, while untested base points remain gray. Only orange points are measured for Euclidean distance, and the code uses d3.svg and SVG circles and rectangles to render the animated search process.

81% match

Quadtree

A quadtree accelerates two-dimensional point filtering in an interactive scatterplot. The visualization shows 2,500 random points that users select by dragging a rectangular brush. Orange points are scanned by the algorithm but not selected, while red points fall within the brush extent. The code uses d3.quadtree to recursively subdivide space and d3.brush for interaction, rendering SVG circles and cell outlines.

78% match

Quadtree

This example demonstrates accelerated two-dimensional filtering using d3-quadtree. A quadtree recursively subdivides square cells into four equal-sized subcells, with each leaf containing a single point from a dataset of 2,500 randomly generated coordinates. When a d3.brush selection is dragged, the quadtree’s visit method only scans points in intersecting cells, coloring scanned-but-unselected points orange and selected points red. The SVG rendering shows the quadtree’s subdivision rectangles in gray, highlighting how the algorithm avoids checking points outside the brush extent.

77% match

Animated Quadtree

This animation demonstrates how a quadtree structure changes as new points are added, displaying each red dot as a point, gray rectangles as leaf nodes, and black lines as internal boundaries. The code uses the `d3_quadtree` JavaScript library with `tree.add`, `tree.visit`, and canvas rendering via `getContext("2d")`. Points are generated using `d3_random.randomNormal` to create a normal distribution centered at the midpoint of the canvas, with each addition triggering a partial redraw to highlight the affected region.

72% match

Scatterplots with D3 and Quadtrees

A scatterplot of 50 randomly generated points uses interactive brushing to highlight selected data, listing their labels and recoloring them in tomato. The implementation leverages a quadtree for efficient spatial lookup, and a "Reveal quadtree" button triggers a slowed animation of the quadtree traversal during brushing. Built with D3 v4, the visualization renders in SVG and uses `d3.scaleLinear`, `d3.axisBottom`, `d3.axisLeft`, and a custom `d3.quadtree` structure.

69% match

Closest Line Segment

A brushless interaction demonstrates nearest-neighbor search over line segments. As the mouse moves, a red highlight identifies the closest segment to the cursor, with the active segment brought to the front. The example builds a binary tree of segment bounding boxes to accelerate the search, using a custom min-heap to prune distant branches. The segment geometry derives from a sine wave, rendered as SVG paths via `d3.geo.path`. The search logic is implemented in a standalone `tree.js` module, while `d3.mouse` handles coordinate tracking.

68% match

Delaunay Triangulation

This interactive demonstration shows a Delaunay triangulation of 100 randomly generated points, with triangles and links redrawn in real time as the user moves the mouse. The first point follows the cursor, highlighting all triangles and links connected to it in red and white. Built with d3.v4 and the d3-voronoi API, it uses SVG paths, lines, and circles to render the triangulation, updating the visualization dynamically on mousemove and touchmove events.