Stephan,<div><br></div><div>Sorry for the delay. I've been away from the office. I'll do my best here to fill you in.</div><div><br><div class="gmail_quote">On Fri, Mar 9, 2012 at 3:14 AM, <span dir="ltr"><<a href="mailto:stephen.pascoe@stfc.ac.uk">stephen.pascoe@stfc.ac.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I'd like to understand better why aggregations are described as they are in ESGF THREDDS catalogs and what LAS expects from them.<br>
<br>
Modern datanodes have 2 levels of nested dataset elements describing aggregations. E.g. [1]. In some cases there are multiple leaf datasets "subset 1" "subset 2" etc. What's the reason for this? Is it to split the field into manageable chunks for TDS or LAS?<br>
</blockquote><div><br></div><div>I believe the reasoning is as follows. Some data sets have large gaps. For example, a run might write out data for a period of 100 years, skip 100 years and then write additional data for 100 years. This makes for challenging user interface issues in LAS since it expects data to be more or less regular and contiguous. So, I suggested that the publisher create separate aggregations where there are these know large gaps in the data. This will allow LAS to think of these things as two separate data sets in the UI and thus guarantee that the UI is presenting only time ranges for which data exists.</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
There are LAS access elements for the dataset at 3 levels of the dataset hierarchy: top-level dataset, first-level aggregation and "subset" aggregation. Are all three of these used by LAS?<br></blockquote><div>
<br></div><div>In the end, no they are not.</div><div><br></div><div>Originally LAS would only load the single variable when that URL of the "subset" was selected and would load all the variables in the data set when the top-level URL was selected. I subsequently changed how the LAS used in the ESGF organized the data sets internally, so that the "top-level" url is the only one that matters and it loads all of the variables in the data set into the interface.</div>
<div><br></div><div>Luca and I were working on this recently and concluded that the publisher should only insert the "top-level" LAS URLs. We could in a subsequent release create URLs at the "subset" level that would load all of the variable into the interface and then select that variable as the active variable. The "first-level" URL seems less useful since we can't determine which subset the user wants. However, neither of these last two options seems pressing or necessary since the search UI does not expose the links to individual variables.</div>
<div><br></div><div>Roland</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Thanks,<br>
Stephen.<br>
<br>
[1] -----------<br>
<br>
<dataset name="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation" ID="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation" restrictAccess="esg-user"><br>
<property name="aggregation_id" value="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation"/><br>
<!-- ... --><br>
<access urlPath="?catid=D9C519D5A310E197819B7197215FD574_ns_cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation" serviceName="LASatPCMDI9" dataFormat="NetCDF"/><br>
<dataset name="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation - Subset 1" ID="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation.1" urlPath="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation.1" restrictAccess="esg-user"><br>
<serviceName>gridded</serviceName><br>
<property name="aggregation_id" value="cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation.1"/><br>
<property name="time_delta" value="1 month"/><br>
<property name="calendar" value="365_day"/><br>
<property name="start" value="2090-1-1 0:0:0.0"/><br>
<property name="time_length" value="1680"/><br>
<access urlPath="?catid=D9C519D5A310E197819B7197215FD574_ns_cmip5.output1.INM.inmcm4.1pctCO2.mon.landIce.LImon.r1i1p1.sbl.20110323.aggregation.1" serviceName="LASatPCMDI9" dataFormat="NetCDF"/><br>
</dataset><br>
</dataset>--<br>
Scanned by iCritical.<br>
</blockquote></div><br></div>