seis.xml: <?xml version="1.0"?> <seisdata> <head> <name>line 101</name> <area>midland</area> <ntrace>1000</ntrace> <nsamp>1501</nsamp> <precision>4</precision> <zstart>0.0</zstart> <zinc>4.0</zinc> <num_xyzs_fields>4</num_xyzs_fields> <xyzs_field_names>xcoord,ycoord,elevation,common depth point</xyzs_field_names> <xyzs_field_precisions>8,8,4,4</xyzs_field_precisions> </head> <xcrd> 123456.712346 123556.712346 123656.712346 123756.712346 123856.712346 ... [ 1000 floating point numbers ] </xcrd> <ycrd> 1234567.812346 1234667.812346 1234767.812346 1234867.812346 ... [ 1000 floating point numbers ] </ycrd> ...
This is a synthetic seismic dataset. It simulates a single 2D line after processing. (Field data have very different data structure because of the highly redundant nature of the acquisition). A 3D dataset might be composed of several hundred such lines, but for most purposes it is very likely that a single line is the unit of data that a Web service would be called on to deliver. That is, if one wanted to pass a full 3D dataset one would probably do it by repeated transmission of data like this. There is a small amount of noise added to these data, which otherwise represent a very simple earth model. The data start out with header information which specifies things like trace number, what location the trace corresponds to, and so on. It then has 1000*1501 numbers which are the traces themselves.
Here are a few of the many differences between this synthetic dataset and real seismic data.