Single quotes around width and height parameters in shortcode do not work

[LeeMcKusick]

If you add the width or height parameters with single-quotes in the shortcode, those values do not get properly passed to the style attribute in the div, and simply fall back on the set defaults.

You need to use double-quotes to have those values passed properly.
This is probably an issue more with shortcodes in general, rather than this Maps plugin in particular, but updating your example would be helpful.