The centerline stationing begins in the center of the channel of the downstream receiving river; in the case of the Lower San Joaquin River, the downstream receiving river is the Sacramento River. At this location, the River Kilometer (Rkm) is designated as Rkm 0. The geographical coordinates for each 1-kilometer Rkm station of the Lower San Joaquin River (Rkm 0 – Rkm 187) are provided. The river centerline coordinate system was created using the wetted area of the river which was first digitized from 2012 National Aerial Imagery Program (NAIP) orthorectified aerial imagery of the Lower San Joaquin River. Next, a continuous line was drawn in the upstream direction following the path of the river in the center of the wetted area. In areas containing multiple channels or large islands, the centerline was drawn though the center of the widest channel.