To display the location of and basic data for seismic lines

To display the location of and basic data for seismic lines

Source Data History: Department for Energy and Mining, South Australia receives seismic line location data from exploration companies as part of their statutory reporting requirements, from Government and Academic institutions and information...

Source Data History: Department for Energy and Mining, South Australia receives seismic line location data from exploration companies as part of their statutory reporting requirements, from Government and Academic institutions and information collected by the department and its predecessors. Data is received digitally in ASCII code and UKOOA format. The data files contain surveyed and/or interpolated seismic shotpoints which define the position of the seismic line. Shotpoint locations from some of the earliest surveys recorded during the 1950s, 1960s and 1970s were not available digitally and were digitised from best available maps. Prior to 1966, the spheroid in general use was Clarke 1858. Many of the surveys from this period were digitised from existing maps and were not converted to the datum currently in use, GDA94, and may therefore be in error by up to 200 metres. Processing Steps: Data received in digital form were checked and corrected as necessary before being committed to the database. The original shotpoint data were processed to filter out and reduce the number of points so that only those points required to define near-straight line segments are retained in the database.
Positional accuracy:The accuracy of the surveyed data is dependant on the survey techniques used to acquire the data and the quality of the horizontal and vertical control to which the seismic shotpoints were connected. The relative accuracy between points, rather than absolute accuracy, is the main criteria in seismic surveying methodology. The absolute accuracy is defined to be within the minimum specifications of (2.5*sqrt(kilometres length of line)) metres for horizontal accuracy and (10*sqrt(kilometres length of line)) centimetres for vertical accuracy. Generally, this accuracy is a factor of 5 times better than the minimum survey specifications. The relative accuracy between points is generally better than a couple of centimetres. The data is stored in the database to 1m precision. The original data is archived in its native format including the original precision which may be quoted to two decimal places.
Attribute accuracy:The seismic line and survey attributes are derived from operational survey reports. Validation checks are performed periodically, resulting in an estimated 95% accuracy. These checks include comparisons between reports from the spatial dataset and other supporting data.
Logical consistency:Highly consistent internally with the exception of a small number (< 5%) of lines which are duplicated and/or have been incorrectly labelled. The majority of these are pre-1970's lines which were digitised.
Completeness:95% complete. For onshore data, information must be submitted within 12 months of survey completion. Data remains confidential for 2 years post survey recording. Offshore data must be submitted 18 months after survey completion and it remains confidential for 3 years post recording.

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