A Google Maps Example using KML (Keyhole Markup Language) generated from a Google Docs Spreadsheet and the map data is then directly inputed into a Google Map.
Use the following spreadsheet as a mapping tool to create advanced KML file for Custom Maps. KML [Keyhole Markup Language] is an XML notation for organizing geographic data and visualizing it.
KML Supports many advanced mapping features:
Create your KML Maps and KML Templates from the start Spreadsheet.
KML -Starter Spreadsheet - Tips:
Use the Longitude and Latitude Google Apps Script to generate co-ordinates. this is in the google apps script gallery within Google Spreadsheets. It is Best to copy and paste the generated co-ordinates in place in the template and in the right order.
On the last page of the spreadsheet unhide the generated KML to create a physical KML file , then you an drag the KML file into Google Earth and save it.
If you use the dynamic KML version through Google Maps - some browsers may need to be refreshed to load the KML information on the fly, thus, better to use a physical KML file for wider browser support.