display every value of a matrix in histogram

Hi all, i need some help with this because i am stucked.

I have a matrix named val which contains180 values (numbers from -90:89) and i wan to put every value on histogram, the code is the below:

%try to find the maimum value on the array to create the xx' axis
rangeTheta=max(abs([lines.theta]));
%ceil to the closest hundred
ceilRangeTheta=100*ceil(rangeTheta/100);

%try to find the maimum value on the array to create the xx' axis
rangeMaxHough=max(val);
%ceil to the closest hundred
ceilRangeMaxHough=100*ceil(rangeMaxHough/100);

figure;title('hough max');hold on;

nbins2=-90:89;
h2=histogram(val,nbins2);

ylim([0, ceilRangeMaxHough]);
set(gca,'YTick',0:100:ceilRangeMaxHough)
 
xlim([-ceilRangeTheta, ceilRangeTheta]);
set(gca,'XTick',-rangeTheta:10:rangeTheta)
 

The proble is that histogram counts the numbers between spaces like around 60 number have value between 150-200 etc.

i want o create a histogram like this, where every row of my array will be displayed on every x bin, and on y axis will be displayed the value of the row, how can i do this?

Answer 1

[dpb]

Ah! The question isn't about a histogram at all...or, it is, but not a histogram of the data but just plot the counts computed elsewhere. That wasn't clear to me before, certainly.

Steven's solution, or

val=val.'; val=val(:);    % orient as vector in row-major order as example shows want...
bins=[-90:89];
bar(bins,val)

NB: If val is stored as you pasted it in as 2D array, you'll have to get it ordered in memory correctly first to plot in the sequence as you show. ML storage order is column-major so as is, would go down columns first, not across rows...

[pasta pontikaki]

the previous code worked thank you very much. The array is not 2D is a 1D vector but i cited as a 2D for convinience.

The result is this tank you very much.

Answer 2

[dpb]

hist(val,unique(val))

[pasta pontikaki]

thank you very much, but still is not working ,i have the same result an empty histogram like the last image.

Also this is not correct because the size of unique(val) is greater (=115) than the x-axis space length (-90:89) which is

length(-90:89)=180

[dpb]

"the size of unique(val) is greater (=115) than the x-axis space length (-90:89) which is

length(-90:89)=180"

Well, that clearly just plain wrong. 115 is certainly < 180 so there are more elements in the space than there are possible indices.

That means there aren't necessarily any elements in some bins -- I presumed would be or that you just wanted bins with nonzero elements. The image certainly won't be blank unles there are all NaN or somesuch which seems incommensurate with the above.

Use

bins=-90:89;
hist(val,bins)

then. If joy doesn't ensue attach the array.

y=randi(20,100,1);
hist(y,unique(y))
xlim([0 21])
xticks([0 20])

results in

There is at least one element in each bin; same result would ensue if used 1:20 instead and an empty bin would also be shown.

[pasta pontikaki]

ok this is the result of hist with 180 bins.

hist(val,180)

I understand whats the problem now. I want the value of every row be puted not on x-axis but on yy'.

I want the x-axis have the range from -90:89 and every value of every row of the matrix be matched with every number of x-axis.

For example row 1 is -90 and if the value is 250 this will displayed on yy' axis. Row 2 is the -89 on x axis, row 3 is -88 etc...

How can i do this?

[dpb]

That's exactly the code I gave you in the follow-up:

bins=-90:89;
hist(val,bins)

It isn't the number of bins you're specifying, it's the bin centers.

That's the advantage the venerable (but sadly, deprecated) hist has over its newer brethern.

[pasta pontikaki]

ok but if i write

bins=-90:89;
hist(val,bins)

the result looks like a brick, and i dont know why this is happening, also the x axis is not right,

The xx' represent the amount of the value that every row have. I want this representation been dispayed on yy' axis

if i put the limits between -90:90 is totally wrong

[dpb]

" the amount of the value that every row have."

I have no idea what the above means.

Attach the data and try again to explain what you think you want.

hist counts the number of elements in a bin..if you're trying to plot something else against a bin, then that will need bar with whatever that something else is...

[pasta pontikaki]

val is a matrix with the below 180 number , so i want o create a histogram with with x-axis vary from -90:89. So every value of the matrix is related to a specific bin in x-axis.

For example the first value is represented with the bin -90 so the value in yy' is 263, the second value is bin -89 so i want to reach until 245 etc

PS I really appreciate your help dude

val=[ 263   245   246   240   229   238   241   244   247   246   251   239   256   242   246   267   268   268
   287   297   266   261   270   299   337   286   282   332   417   578   458   320   334   374   319   323
   344   351   359   324   356   362   327   282   286   258   244   233   215   210   202   213   199   212
   196   200   192   196   194   183   182   183   185   184   191   195   178   177   184   174   179   175
   166   171   174   166   169   155   157   161   169   161   163   156   154   153   157   157   154   152
   150   156   156   152   153   163   161   161   164   152   155   160   158   158   158   164   161   160
   163   167   170   177   187   203   200   209   218   230   275   280   350   429   428   379   421   331
   313   371   384   397   393   374   397   422   386   388   392   301   261   255   252   240   241   244
   259   254   243   243   242   252   247   252   247   243   254   245   237   234   236   235   241   244
   243   242   237   237   234   225   235   231   236   234   229   231   234   243   246   237   232   237]

Answer 3

[Steven Lord]

Does the data represent the counts for each of the bins? If so call histogram and specify the BinEdges and BinCounts name/value pairs. See the description of the counts input argument on the histogram documentation page.