How to create a custom profile field

Hi guys.
I want to create a field so that members can select their Geo locations on google maps. This field should contain the longitude and latitude (may be i need to create two fields?). But I don't know how can i create a new profile field. Please help!!

I'm using Elgg 1.9.x

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking