Since Maps Marker Pro v2.6 you can automatically add links to your KML maps to your XML sitemaps easily, as support for the popular plugin Google XML sitemaps has been added. Please see the release notes for more details.
If you are using another sitemap plugin, you can manually submit your geo sitemap to Google by following this tutorial:
- Login on https://www.google.com/webmasters/tools/
- On the Webmaster Tools home page, click the site you want to modify or create a new one
- Navigate to Crawl and open the submenu Sitemaps.
- Click the Add/Test Sitemap button.
- In the text box, complete the path to your Sitemap, for example https://www.yourdomain.com/maps/geositemap
- Click Submit.