Abstract: A position location and marking system includes a base unit having stored data location files and communication apparatus therein together with a cooperating mobile element which communicates with and aides in location under the control of the base unit. A robotic marker is provided with battery-powered self-propulsion and directional control and receives and supports the mobile element of the positioning system. A sprayer is also supported upon the robotic marker and is maintained in alignment with the position detecting portion of the mobile unit by a gimble system. An onboard controller is also supported upon the robotic marker to control robotic movements and spray operation in response to communicative position and location data.