Why does the size of the map change when I change the

Understanding Axes Behavior in MATLAB Maps

When MATLAB axes limits are set to 'auto', they adjust automatically based on the map's radius. For a map with a 30-degree radius, the projected map unit radius is 0.5, and the axes limits adjust accordingly. For a 40-degree radius, the projected map unit radius is approximately 0.6453, causing MATLAB to round the XLim and YLim properties outward to [-0.8, 0.8]. This results in the map occupying a smaller portion of the axes.

Solution: Using TIGHTMAP for Better Fit

To make the map fill the axes, call TIGHTMAP after plotting. This function checks the map frame polygon limits in the map's X and Y dimensions and manually adjusts the axes limits to match.