[LDM #JTZ-993835]: LDM Question

["Unidata LDM Support" <support-ldm@xxxxxxxxxxxxxxxx>]

Steven,

> We use LDM to get Forecasted River Stages from the National Weather Service
> and it works great.  We just started receiving Forecasted Flow Data from
> them, however, they are sending the flow data in kcfs (thousand cfs), instead
> of being cfs.  Therefore, we need to take their data and multiply it by 1000
> to get it into our database correctly.
> 
> 
> The question I have is, is there a way in LDM to do the math before it sends
> it out?  For example, the pqact file tells where to put the data.  Is there a
> way to do the math before it sends it out?

By "send it out" I assume you mean that you want your receiving LDM system to
transform the data before relaying it to additional LDM's under your control.

No, the LDM can't, itself, perform such an operation.  You can, however, use
the capabilities of the LDM to accomplish this with a little programming effort.  
Use the PIPE action of "pqact" to convey the data-products to be transformed
to a utility that will perform the conversion, generating a new data-product.
Then insert that new data product into the product-queue, using a new product-
identifier that identifies it as the converted data-product.  To save
development time, the conversion utility could be written in a scripting
language (e.g., Perl, Python), providing it doesn't consume to much of the
CPU.  If a script is used, then its output file could be inserted into the
product-queue as a new data-product via the "pqinsert" utility.

> Thanks,
> 
> Steve
> 
> Steve Simmer
> Reservoir Regulation Team
> New England District - COE
> (978)318-8524


Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: JTZ-993835
Department: Support LDM
Priority: Normal
Status: Closed