Spraying mapping

 This kind of mapping is ideal when the operator is defined analytically, or quasi-analytically, as a function of few parameters of the input and output geometries. Examples of this kind of operators are DMO, AMO, and stacking. Often the output space of these operators is more effectively defined in an input-centered coordinate system. Therefore, when the spraying mapping is applied, the data are first mapped into an intermediate output space, and then spatially interpolated and summed into the final output space. Therefore, two functions must be defined: the oper_domain function that defines the operator domain, and the map_amp that describes the integration surface.

This mapping requires that the data structure that describes the geometry of the whole output space (out_geom) is passed to genkir3d. The access to the output data can be blocked along the offset and azimuth dimensions by specifying e geometry of the blocks with the argument out_geom_block. To optimize the access to the input data, the inner loops over the output space are in the offset and azimuth coordinates (aoffset and azimuth) of out_geom_block.

An ungridded data set is accessed sequentially. The data are read multiple times, as many times as the number of output blocks. A gridded data set is accessed selectively according to the offset and azimuth of the output block being currently built. Each data trace is read only once.