dataselect -SDS writes weekly files instead of daily files

[CoralieAubert]

Hello,

I converted a weather station data to miniseed. First, I wrote all the data in a single miniseed file and I used dataselect -SDS option to split the data into daily files and store them in the appropriate SDS archive.

I do not know why the output of dataselect -SDS option is not daily files but 7 days files. The period of the samples is 600 sec.

I attached 2 print screens of the miniseed stats:

• Full miniseed files
• 2 weekly miniseed files after dataselect -SDS

Do you have any idea? Regards, Coralie

[chad-earthscope]

Hi @CoralieAubert,

I don't see the dataselect command you ran, but if you ran it just with input, output and the -SDS option, note that by default the program is not splitting data records. So is placing individual miniSEED records (small segments) into the SDS file according to the start time of the record. But with relatively long sampling intervals such as you describe this means a single record can span multiple days.

To also have the program split data records you need to add the -S option to split on day, hour or minute boundaries. To match the SDS daily file scheme, use the -Sd option to split records on days, like so:

dataselect <INPUT.mseed> -Sd -SDS <sdsdir>

Note that due to the nature of miniSEED this option will create unfilled records (or less filled than the input), using more storage space than the original data. Likely this is not important for small data sets, but for large data sets can make a huge difference.

If I've misunderstood what you were trying to do, please let me know what commands you ran.

[CoralieAubert]

Hi,

I was using the datselect -Ps -SDS options only.

I tried '-Sd' option which works perfectly. I was looking for such an option in the dataselect manual but I did not find. This option is not included in the manual, right? Thanks for your help, it works fine.

Regards, Coralie

Le 14/04/2020 22:13, chad-iris a écrit :

Hi @CoralieAubert https://github.com/CoralieAubert,

I don't see the dataselect command you ran, but if you ran it just with input, output and the -SDS option, note that by default the program is /not/ splitting data records. So is placing individual miniSEED records (small segments) into the SDS file according to the start time of the record. But with relatively long sampling intervals such as you describe this means a single record can span multiple days.

To also have the program split data records you need to add the |-S| option to split on day, hour or minute boundaries. To match the SDS daily file scheme, use the |-Sd| option to split records on days, like so:

|dataselect -Sd -SDS |

Note that due to the nature of miniSEED this option will create unfilled records (or less filled than the input), using more storage space than the original data. Likely this is not important for small data sets, but for large data sets can make a huge difference.

If I've misunderstood what you were trying to do, please let me know what commands you ran.

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[chad-earthscope]

Glad to hear that the option worked.

It is documented in the man page (this is the man page converted to Markdown): https://github.com/iris-edu/dataselect/blob/master/doc/dataselect.md

It's under the -Pe option.