# Why MatOfPoint is list of points?

Hi, I'm quite new in OpenCV and image processing, I'm trying to understand findContours function and handle it's result, particularly I have to detect from image discrete graph and the number written for each edge. I guess I should start with finding contours and than somehow extract from it numbers. I have several questions.

- Why MatofPoint is list of points?
- I convert contour to the List<list<point>> and I wonder what defines the size of each list, as it can be any number 1 or 112...
- Is it possible to make matching beetwen screen coordinates and org.opencv.core.Point?

Could you, please, help me understand theese basic but main concepts, as I searched and read a lot but can't find answers.

P.S. Any blogs/links where I can find tutorials to successfully getting started with image processing wil be appreciated.

take a look at the related tutorials

I've already read it, thanks a lot for your help! :)))

"I have to detect from image discrete graph and the number written for each edge" -- can you explain a bit more ? like a freeman chain ?

Here is a sample image https://imgur.com/a/lHlwN I need to have coordinates of graph nodes and lenght for each edge.