Seismic Geometry seisGeomType extSeisGeomType refinedSeisGeomType refinedExtSeisGeomType POSC 1.0 VSP survey The geometry describes a VSP survey, in which seismic receivers are placed at various positions within a borehole, and the shots are at the surface. 2D survey The geometry describes a survey in which shots and receivers fall along a single line. 3D survey The geometry describes a survey in which shots and receivers cover a nontrivial area, and the CDPs are intended to cover a two dimensional area. 2D line The geometry describes a seismic line, which is extracted from a larger, usually 3D survey. line segment The geometry describes a seismic line which is a segment of a larger seismic line. source line The geometry describes a line of source events. This is generally used in a 3D survey in which there are many types of lines. reciever line The geometry describes a line of receiver stations. This is generally used in a 3D survey in which there are many types of lines.