Comments (5)
Released in 1.1!
from d3-contour.
Seems like geom_density2d defaults to a grid size of 100×100 (n
defaults to 100) and by default uses bandwidth.nrd as the Gaussian kernel. I’m guessing that should map pretty closely to a stack blur radius.
from d3-contour.
Random thought - A 1D version of this Gaussian kernel would be a really nice addition to D3, possibly as a sibling of d3-array#histogram. I see this was worked on long ago in d3/Add kernel density estimation. PR #143.
from d3-contour.
Here’s a related example (just updated): https://bl.ocks.org/mbostock/4341954
That example computes the kernel density estimation the brute force way: it evaluates the kernel for each data point (n) for each grid point (m) = O(nm). This tends to be prohibitive for estimating two-dimensional density since the number of grid points in two dimensions is much larger (e.g., m = 480×250 = 120,000 instead of m = 100).
One way of making the brute force method faster would be to sort the data, and then keep a moving window of data points whose kernel value is non-zero. Although if your bandwidth is large, then this wouldn’t be a big improvement, since you’d still be evaluating the kernel on a large number of data points for each grid point.
Or you could use the same fast blur technique d3-contour uses for two-dimensional density estimation. This is less accurate because the data points are first rounded to the resolution of the grid before blurring, but often this is acceptable.
from d3-contour.
I really like the idea of blur(histogram(data))
.
from d3-contour.
Related Issues (20)
- Release d3-array v2 compatible version? HOT 2
- hole issue in contour HOT 5
- Arrows using elevation value for any point(x, y) in contour chart HOT 5
- GeoJSON Geometry which is generated by d3.contour displays wrong HOT 3
- output data has index which is not exist in input data HOT 2
- Feature request: contour labels HOT 2
- smoothing removes line segements HOT 1
- Buggy input check in density size setter.
- Improve slow computations for large images HOT 2
- Handle Null values in grid HOT 9
- Dependencies HOT 3
- Some contour polygon is reverse. HOT 5
- Support fractional bandwidths. HOT 2
- [feature]: cellSize(0.5) would work well in d3.contourDensity() HOT 1
- Support curvilinear grids HOT 11
- Sometimes the lowest threshold is missing
- Bug HOT 2
- Breaking change with contour-density thresholds starting from v3.0.2 HOT 2
- isobands?
- Don’t round the corners HOT 8
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from d3-contour.