As is usually the case, soon after I published the first draft of SaneSeis, I realised I was missing things, and that with a few additions could make it better.
The biggest change in this updated version is the addition of a Receiver Table after the Source Table.
I was very reluctant to add another variable length block, but the advantages outweigh the drawbacks. And in any case each entry within a table is fixed length, and the number of entries are defined in the file header, so, unlike SEGD it is very easy to calculate memory requirements and start of data.
The latest updates can be seen here: http://seismatters.com/SaneSeis.html
Other notable additions
- Record type. Currently based on Sercel’s 428 definitions, there is plenty of room to add more
- Recorder position. This seems to have been forgotten these days, but is still good information to have. SaneSeis records the Low Line/Point of where the recorder connects to the spread.
- Source position mode in the source table. We need to know if the source position is the true position from the source navigation system or preplanned or something else.
- Limits have been removed from the trace header – they are now in the Receiver table. This saves 20 bytes per trace header which on a big survey can add up to a useful saving. Resistance/Tilt/Capacitance errors are now indicated by 255=low, 0=in range, 1=High
So far very little feedback. PS has suggested that I incorporate EPSG codes. I am looking at this, but I do want to keep everything metric, so will not support feet, yards, miles etc. It is only the US that still uses these and it is about time they moved into at least the 18th century. SaneSeis coordinates must also remain Cartesian, so not all EPSG codes would be valid.
Comments and suggestions welcome.
http://seismatters.com/cgi-bin/feedback.cgi