There is a
Download SVG with Google Map button on MapSVG start screen. What does it do?
If want to overlay interactive vector graphics on top of the Google Map,
you should download a calibrated SVG file with the Google Maps screenshot, edit the SVG file in Inkscape and then upload the file back to MapSVG.
Your vector graphics will be automatically overlayed on the Google Map by MapSVG.
See more info on this page: Google Map with custom SVG overlay