I have some grid data (m*n matrix) of the surface ocean, extending to the land in some areas. I have the conterminous United States map as a circle. Is there a way that I can blank everything that lies inside the map circle?
MATLAB: How to blank data within a circle
nan
Related Solutions
Assuming:
- your image is grayscale and is called img;
- the central pixel is at column x and row y;
- the radius of the circle is r;
- you do not require weighting at the rim of the circle - that is, each pixel is either entirely inside or entirely outside the circle;
then you can do something like this
[xgrid, ygrid] = meshgrid(1:size(img,2), 1:size(img,1));mask = ((xgrid-x).^2 + (ygrid-y).^2) <= r.^2;values = img(mask);where values will have a column vector containing the values in the circular region.
See my attached masking demos. They show a variety of different ways you can mask an image, such as to blacken outside an ROI.
Best Answer