# [R] Frequencies from x/y data into a 2d table (for 3d histogram or heatmap)

Marcio Pupin Mello mello at ieee.org
Wed Feb 29 22:38:18 CET 2012

```Hi David,
thanks a lot! Actually, I was looking for the graph since I still
have obtained the table... but It can help...
Best,

Marcio
www.dsr.inpe.br/~mello

On 2/29/12 5:34 PM, David L Carlson wrote:
> Something like this?
>
> x<- round(runif(100, 0, 40), 0)
> y<- round(runif(100, 0, 40), 0)
> xgroup<- cut(x, seq(0, 40, 10), include.lowest=TRUE)
> ygroup<- cut(y, seq(0, 40, 10), include.lowest=TRUE)
> xy<- table(xgroup, ygroup)
> image(xy)
>
> You'll still have to work with the plot commands to label it properly.
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of Marcio Pupin Mello
> Sent: Wednesday, February 29, 2012 12:49 PM
> To: r-help at stat.math.ethz.ch
> Subject: Re: [R] Frequencies from x/y data into a 2d table (for 3d histogram
> or heatmap)
>
> Hi Ralf,
> have you solved your problem?! If so, could you share? I have the same
> problem...
> Best,
>
> Marcio
>
>
> On 3/25/10 6:03 PM, Ralf B wrote:
>> Hi all,
>>
>> I have simple x/y data from screen recording in a sequence:
>>
>> number,x,y
>> ----------------
>> 1,10,30
>> 1,20,
>> 1,43,110
>> 1,74,18
>> 1,88,112
>>
>> and would like to create a 3d histogram data structure that i can use
>> to create a 3d histogram or, more likely a heatmap. The unterlying
>> data structure therefore needs to look like this:
>>
>>             0-10        11-20         21-30        31-40
>> 0-10
>> 11-20
>> 21-30
>> 31-40
>>
>> where the values in the cells represent counts of datapoints fitting
>> respective ranges for x and y. Can somebody point me to a procedure in
>> R that can make such a transformation for different range sizes (i.e.
>> 10 in my example)? I came across the following method:
>>
>>
> https://stat.ethz.ch/pipermail/r-help/attachments/20070425/fcb92205/attachme
> nt.pl
>>
>>
>> which seems (at least close) but did not get it running (could not
>> find clear3d()). I also dont' need the 3d histogram plot as I will be
>> using the table to create a heatmap. I might be thinking to
>> complicated here. To me, it seems like this should be possible with a
>> few lines of code. Perhaps one of you has them lying around somewhere
>> or knows a script that does the trick.
>>
>> Thanks in advance!
>>
>> Ralf
>>
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

```