The pipeline locator/coordinate mapping device is a tool to be utilized for the location of pipeline coordinate data points via a Cartesian coordinate system. The device will initiate from a known origin or datum with horizontal, X coordinate; longitudinal, Y coordinate; and vertical, Z coordinate respectively being equal to zero. As the device traverses internally through the pipeline, away from the origin or datum, a time increment will correspond to the recorded data, pressures and accelerations, and hence allow the positional coordinate points along the pipeline to be derived in three dimensional space for incremental positions versus time. By analysis of the data displacements from the origin or datum in succession, the pipeline may be located and mapped in an as-built position from a frame of reference, i.e. longitudinal and latitudinal coordinates along the earth.