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Re: [las_users] overriding subsampling
Hi Upendra, hi Ansley,
You could switch striding off in the ferret code. I did this for Time
Series in LAS 7.1.2, by changing the code in
/JavaSource/resources/ferret/LAS_initialize_variables.jnl in line 141 to
IF `($num)+1 EQ ($data_count)` THEN
IF ($operation_service_action%|Plot_2D_XY>TRUE|*>FALSE%) THEN
GO LAS_set_strides.jnl
ENDIF
ENDIF
It works fine for me, so only for Plot_2D_XY (Maps) the script
LAS_set_strides.jnl will be executed.
Regards,
Remon
On 06/10/2011 12:25 AM, Ansley Manke wrote:
Hi Upendra,
Subsampling is in LAS to prevent overly large data requests, and is
done in a way to try to minimize the effect on the end result. It is
not done for data downloads, only graphics.
The Ferret scripts compute the amount of striding based first on the
amount of memory available to Ferret running as the backend. Next,
they compute the size in pixels of the output image and base the
amount of sampling on that - if there are 600x800 pixels then we won't
get a better 2D image by using full-resolution data that is larger
than that. Time series plots may lose some extreme values of course,
so there's an argument for allowing control in some cases. If the time
series is being extracted from, say, an aggregation of many large
datasets, it can create huge requests, so one wants to think it
through. Allowing control that at the level of the LAS installer means
that you could decide when to turn this on or off.
Right now there's not a way to override this in the configuration but
it could be added. I'll write you off-line and we can talk about some
ideas.
You're quite right that we need documentation that lists the Ferret
properties that can be used for customizing dataset configurations.
I've added an item to our to-do list to create that.
Ansley
On 6/9/2011 1:31 PM, Upendra Dadi wrote:
Hi,
For some of the time series graphs, LAS puts the following on top of
the graph "Subsampled x in T". How do I override subsampling and show
the entire data? Is there a Ferret property I need to override? Also,
is there a list of mapping between Ferret properties and the
corresponding LAS XML tags. Please help. Thanks!
Upendra
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