Re: [las_users] Moving Date Windows

[Roland Schweitzer <Roland.Schweitzer@xxxxxxxx>]

Phil Cogbill wrote:
> I was just curious, but we have datasets that have a moving window.  We
> have datasets that only have the last year of data available rather than
> the entire period of record because it would be much too large to store
> on spinning disc.  The older data is removed (but stored on a archive
> system) and the new data is appended. The window of data that is
> available on spinning disc is known. 
>
> ie.) May 15th, 2009 - May 15th, 2010
>
> LAS seems to know something is wrong. 
>
>  **ERROR: illegal limits: VVEL does not exist at T=15-JUN-2010 00:00
>           Axis extremes are T=15-MAY-2009 21:00:15-MAY-2010 21:00
>
> Is there a way that LAS can detect this and render the correct dates in
> the interface?
>   

Phil,

We are aware that this is a common use case and we have made a few 
attempts to fix the problem within LAS, but as of yet we don't have a 
working solution.

Right now, the only way LAS can render the correct dates into the user 
interface so that the user cannot select a time that is not available is 
if the configuration information that it has read into memory matches 
what's available in the dataset.  To keep data sets like those you 
describe in sync requires some external intervention.

The most common way to solve the problem now is to run a cron job that 
edits or recreates (using addXML) the configuration information for the 
data set.  Once the configuration has been updated, then LAS can be 
coaxed into re-initializing itself from the admin interface.  If you 
configure the admin interface you can do the re-initialization manually 
by clicking the link.  But, in most cases you want the re-initialization 
to happen automatically.  To do that you can hit the re-init URL from a 
cron job script using wget.  The trick is that the URL typically 
requires authentication.

You have two choices, you can hit the link using a URL that contains the 
login information in the standard 
http://login:password/server.gov/reinit.do.  That leaves your LAS admin 
password lying around in plain text, which is not ideal.  You can also 
configure LAS so that the reinit link does not require authentication 
and block access to the link from outside the firewall.  Again, none of 
this is even remotely close to ideal, but it's the best we have right now.

We have it on our todo list to provide some better solutions.

Roland
> Thanks for the input,
>
> Phil
>
>