plotting - Make a density list plot/histogram from large, pre-binned data set?

I have a large data set consisting of $\mathcal{O}(10^9)$ two-dimensional points. In order to save memory and time I have pre-binned these into a uniform grid of $500 \times 500$ bins using Fortran. When imported into Mathematica 8.0 as a table the resulting data look like:

data = {{0.388348, 0.388349, 9},{0.388348, 0.776699, 23},...},

where the first two items of each entry correspond to the $x$-$y$-coordinates of the upper-right-hand corner of the bin and the third is the count.

Edit:

For a sample of the raw data, raw=RandomReal[1,{1000000000,2}] is a good approximation. This is obviously unworkable.

For the binned data: binned=Table[{.01*Ceiling[raw[[i,1]]/.01],.01*Ceiling[raw[[i,2]]/.01],RandomInteger[1000]},{i,1,250000}].

I would like to plot this pre-binned data set in the form of a DensityHistogram, but my data format doesn't fit into what this function is expecting. I have reviewed a similar question for one-dimensional histograms at Histograms with pre-counted data, however I'm at a loss as to how to apply this to 2-D. I have also looked at doing

Image[Rescale[data]]

on the raw data. However, this crashes immediately with a SIGSEGV error that has the Wolfram Support team puzzled. Consequently, I haven't gone very far down this road.

Edit:

I have also tried ListDensityPlot[data,InterpolationOrder->0]. For the full data set, Mathematica hangs for over 10 minutes, at which point it runs out of memory and the kernel shuts down. For a subset of the data, I get something more reasonable, but I would need some way to scale this up to $500^2$ data points.

Making these plots seem to be something that is fairly easily done in Matplotlib, but I have already made some other plots in Mathematica and don't want to mess with different styles. I'm fairly new to Mathematica and don't have a good knowledge of all the functionality, unfortunately.

So, how can I make a DensityHistogram when the bins and counts have already been calculated?

Comments

plotting - Filling between two spheres in SphericalPlot3D

Manipulate[ SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, Mesh -> None, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], {n, 0, 1}] I cant' seem to be able to make a filling between two spheres. I've already tried the obvious Filling -> {1 -> {2}} but Mathematica doesn't seem to like that option. Is there any easy way around this or ... Answer There is no built-in filling in SphericalPlot3D . One option is to use ParametricPlot3D to draw the surfaces between the two shells: Manipulate[ Show[SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], ParametricPlot3D[{ r {Sin[t] Cos[1.5 Pi], Sin[t] Sin[1.5 Pi], Cos[t]}, r {Sin[t] Cos[0 Pi], Sin[t] Sin[0 Pi], Cos[t]}}, {r, 1, 2 - n}, {t, 0, Pi}, PlotStyle -> Yellow, Mesh -> {2, 15}]], {n, 0, 1}]

plotting - Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen many examples using functions to define color but my wavelength cannot be expressed by an analytic function. Is there a simple way to do this? Answer Here a another possible way to visualize 4D data: data = Flatten[Table[{x, y, x^2 + y^2, Sin[x - y]}, {x, -Pi, Pi,Pi/10}, {y,-Pi,Pi, Pi/10}], 1]; You can use the function Point along with VertexColors . Now the points are places using the first three elements and the color is determined by the fourth. In this case I used Hue, but you can use whatever you prefer. Graphics3D[ Point[data[[All, 1 ;; 3]], VertexColors -> Hue /@ data[[All, 4]]], Axes -> True, BoxRatios -> {1, 1, 1/GoldenRatio}]

plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1.

Blog

Search This Blog