Filling a map with colours

Dear all

I have a map for a country as .bmp. I then transfer this image to MATLAB using imread, and then visualise it using imagesc. Since this is a map with different regions, I would like to fill those regions with different colours based on a variable. There are 20 regions and I have 20 values for every region. I would like to fill different shades of green in those 20 regions and then assign a colorbar to the map. Could someone please tell me if there is a function for filling colours in different regions on a map?

Thank you for your help.

Suha

Answer 1

[Walter Roberson]

The map for the country that you read: is the value that you read a region number, and 0 for the places that are not inside the map?

If so then see https://www.mathworks.com/help/images/ref/label2rgb.html

[Suha]

Thank you, Walter. That map was made in Paint hence every region has a range of numbers. There is no consistency (i.e. one region does not have a unique one number). Is there a way in MATLAB where I could assign one number to one region of the map, and second number to second region etc. so that I can eventually use label2rgb for filling in the colours? Thanks

[Walter Roberson]

How do you know which part of the map is which region ?

[Suha]

In a coding sense, it's hard to know because it's made up of random numbers, but when plotted using imagesc, I know which section corresponds to which region, and what colour I want in that region. Not sure if there is a way in MATLAB where I can specify (by clicking) that this is region 1, hence assign one number to it.

[Walter Roberson]

See https://www.mathworks.com/matlabcentral/answers/306359-challenge-how-to-interact-with-matlab-figure-using-mouse-events#answer_238107

[Image Analyst]

Try imquantize() to get each region down to a unique gray level (index).

[Suha]

Thank you !!