How can I change my X axis on a earth satellite picture to reflect geo coordinates [90 -45] on the longitude passing through the international date line of long=180?

I have a satellite picture of the northern hemisphere covering part of Asia and all of the US. I have loaded the picture in and can get the Latitude to read [0 90] but even when I create a custom vector for the Longitude going from 90-180 then -180 to -45 and apply the vector as the new X axis in the image, Matlab only takes the end points of my custom vector [90 -45] and forces all other points to eventually pass through 0. Is there a way I can tell Matlab that these are Longitudinal coordinates and label my X axis [90...180, -179, ....-45]?