You can contribute to the Anza Trail online interactive map

The National Park Service is using MapCollaborator as a "web-based mapping tool and database for Anza Trail Partners (agencies, non-profits, volunteers) to assist NPS in documenting the Anza Recreational Trail and its resources. Once approved by NPS staff, data entered on this site will be shared on our public website at www.mapsportal.org/anzatrail."   Here's a screen shot of a photo from Painted Rock Petroglyph Site along the trail, that pops up once the map site is clicked.