How to plot (x,y,z) points showing their density

Question

My data file is a set of (x,y,z) points located around the axis origin. They represent points where a kind of measure has failed. These points are in this link.

Gnup

Answer 1

@user1993416, I guess you can do something with gnuplot. You might need to play with the parameter Delta. With my 8 year old computer 1000 points need approx. 2 minutes.

The followig code:

### 3D density plot
reset session
set term wxt

N = 1000      # number of datapoints
Delta = 2    # half boxwidth

TimeStart = time(0.0)
# create dummy some dummy data
set samples N
set table $Data
    plot '+' u (invnorm(rand(0))):(invnorm(rand(0))):(invnorm(rand(0))) with table
unset table

# put the datafile/dataset into arrays
stats $Data nooutput
RowCount = STATS_records
array ColX[RowCount]
array ColY[RowCount]
array ColZ[RowCount]
array ColC[RowCount]
do for [i=1:RowCount] {
set table $Dummy
    plot $Data u (ColX[$0+1]=$1,0):(ColY[$0+1]=$2,0):(ColZ[$0+1]=$3,0) with table
unset table
}

# look at each datapoint and its sourrounding
do for [i=1:RowCount] {
    print sprintf("Datapoint %g of %g",i,RowCount)
    x0 = ColX[i]
    y0 = ColY[i]
    z0 = ColZ[i]
    # count the datapoints with distances <Delta around the datapoint of interest
    set table $Occurrences
        plot $Data u ((abs(x0-$1)<Delta) & (abs(y0-$2)<Delta) & (abs(z0-$3)<Delta) ? 1 : 0):(1) smooth frequency
    unset table
    # extract the number from $Occurrences which will be used to color the datapoint
    set table $Dummmy
        plot $Occurrences u (c0=$2,0):($0) every ::1::1 with table
    unset table
    ColC[i] = c0
}

# put the arrays into a dataset again
set print $Data
do for [i=1:RowCount] {
    print sprintf("%g\t%g\t%g\t%g",ColX[i],ColY[i],ColZ[i],ColC[i])
}
set print

TimeEnd = time(0.0)
print sprintf("Duration: %.3f sec",TimeEnd-TimeStart)

set palette rgb 33,13,10
splot $Data u 1:2:3:4 w p ps 1 pt 7 lc palette z notitle

set terminal gif animate delay 30
set output "Density.gif"
Amin = 40
Amax = 60
AFrames = 25
do for [i=0:AFrames] {
    print sprintf("Frame %g, Angle: %.1f", i, sin(2*pi*i/AFrames)*(Amax-Amin)+Amin)
    set view 45,(sin(2*pi*i/AFrames)*(Amax-Amin)+Amin)
    replot
}
set output

should result in: