quadtree

问题 I am trying to use and understand the D3 visualization library (http://mbostock.github.com/d3/), and I am looking at their force directed code and it seems they are using a quadtree to calculate the force on a particle. The code is var k = kc * quad.count * dn * dn; node.px -= dx * k; node.py -= dy * k; where it seems thay quad.count is the number of particles in the quadtree node. But looking at their quadtree code in https://github.com/mbostock/d3/blob/master/d3.geom.js#L696, I can't find

问题 All, There are a few examples on implementing a quadtree using Python but my question is, does anyone know of a class written in pure python as in a single .py file that I can easily include in my project? The three most popular packages are listed here Are any of these quad-tree libraries any good? but I have not had luck with using them because of all the dependencies required to run them. I am really going for something lighweight and relatively simple to use. I would like to call the

问题 I am writing a quadtree class as a part of graphics library and I am facing a design issue. A main goal is to allow the user of the library to easily extend the quadtree with their own Node Types. Each node has a pointer to the first of its four childs. I use the protoype pattern to 'clone' a parent node (its real type is unknown to the library) four times when it is split. So here is the Node class: class CNode { public: virtual CNode* clone(); protected: CNode* pChilds; } The user of the

问题 I have been looking for a quadtree/quadtree node implementation on the net for ages. There is some basic stuff but nothing that I would be able to really use it a game. My purpose is to store objects in a game for processing things such as collision detection. I am not 100% certain that a quadtree is the best data structure to use, but from what I have read it is. I have already coded a Red-Black tree, but I don't really know if the performance would be good enough for my game (which will be

问题 I have a number of tile sources which utilise Bing Maps' Quadkey system in an old Silverlight application and I would like to use them in a new Openlayers 3 map. I have found several examples of functions which will convert these sources for Leaflet.js but the syntax is somewhat different for OL3 and reading through the API docs indicates that there is an ol.Tile.coord class but if I understand correctly this is an experimental feature and might require a custom build from the source code.

问题 I'm in the process of creating an offline Slippy Map using QML and their new QtLocation module (>=Qt5.4). I managed quite easily to display the tiles with an offline cache. Now I would like to add custom data to this map (a list of ~7000 airports). This huge list would have to be clustered depending on the zoom level (for performance and readability reasons, unless the QtLocation has built-in "optimizations"..?. What would be to most elegant/best way to achieve this, staying as close as

问题 I have recently learned about binary space partitioning trees and their application to 3d graphics and collision detection. I have also briefly perused material relating to quadtrees and octrees. When would you use quadtrees over bsp trees, or vice versa? Are they interchangeable? I would be satisfied if I had enough information to fill out a table like this: | BSP | Quadtree | Octree ------------+----------------+------- Situation A | X | | Situation B | | X | Situation C | | | X What are A,

问题 I have a set of 100 to 200 points (x,y). I have to check which ones fall within a particular distance of the others. The particular distance is fixed for the entire program, say 50. Say point 1 falls within the range of points 5,7,25,90,96,105...etc. Similarly point 2 falls within range of 23,45, etc... Storing objects for locating by x,y coordinates Here QuadTree is suggested, but it can be used to get all the points within a bounding rectangle. But how to get all points within a bounding

问题 I have a set of 100 to 200 points (x,y). I have to check which ones fall within a particular distance of the others. The particular distance is fixed for the entire program, say 50. Say point 1 falls within the range of points 5,7,25,90,96,105...etc. Similarly point 2 falls within range of 23,45, etc... Storing objects for locating by x,y coordinates Here QuadTree is suggested, but it can be used to get all the points within a bounding rectangle. But how to get all points within a bounding

问题 I have a following path data: id1 p1 p2 0 1 7.935 5.103 1 1 7.934 5.112 2 1 7.936 5.102 3 1 7.938 5.145 4 2 7.930 5.191 5 2 7.945 5.161 6 2 7.954 5.127 In the above data frame, (p1,p2) forms the coordinate data and all the points belonging to the same "id1" forms one separate path; in the above df rows(0-3) belonging to id1 = 1 is one path and so on. I am trying to implement Quadtree for the analysis of these trajectories. To implement Quadtrees I am trying to use "pyqtree" https://github.com