Why pdf value of gaussian Mixture Model (GMM) is greater than 1?

I use GMM to built two prior models for sea_samples and land_samples. what is the probability of the data point (xi) belongs to sea_samples? i utilize pdf method but, the value is greater than 1

example:

GMM_sea=fitgmdist(RGB_sea_samples,2);
GMM_land=fitgmdist(RGB_land_samples,5);
pdf(GMM_sea,RGB_sea_samples);
pdf(GMM_land,RGB_land_samples);

Answer 1

[Walter Roberson]

Remember that pdf is probability density, not probability. It is the integral of the pdf over the range that must be one, which means that the pdf can be up to 1/(width of interval)

[Eman Elkhateeb]

what can I do when computing the likelihood that the pixel i belongs to class sea or land

[Walter Roberson]

Unfortunately I have not used GMM, so I do not know how you would compute that.

Answer 2

[Jeff Miller]

As I understand the question, the answer only depends on the pdf's, not on where they came from (here, GMM).

    GMM_sea=fitgmdist(RGB_sea_samples,2);
    GMM_land=fitgmdist(RGB_land_samples,5);
    pdf_sea = pdf(GMM_sea,RGB_sea_samples);
    pdf_land = pdf(GMM_land,RGB_land_samples);
    Pr_sea = pdf_sea*prior_sea / (pdf_sea*prior_sea + pdf_land*prior_land);
    Pr_land = 1 - Pr_sea;

I think that Pr_sea and Pr_land are the probabilities you are after. prior_sea and prior_land are the overall proportions of sea and land creatures of whatever type you are studying.