The IEM uses Unidata LDM to move data around within the computing infrastructure. Anybody is eligable to request a LDM feed, so to get products pushed to you without any fuss! This page details the setup of the LDM feed.
Looking for low latency ASOS data? Read this first!
TL;DR There is no latency magic with the IEM LDM Feed.
The IEM continues to get incessant emails believing that the IEM offers some magic feed of ASOS data with reduced latency allowing for gambling edge. Please see Wagering on ASOS temperatures for related info on this topic. While LDM is a push technology that does offer products faster than what you could see off of government websites with CDN / caching, it is also sourced from a data stream that bounces off of geostationary satellites, which will have many seconds more of latency vs folks that have a direct from FAA Internet feed. Again no IEM LDM magic here, but you insist there so, so we continue...
MADIS processes a stream of data from the FAA with reduced latency, but has a major quick with temperatures reported in Whole degree Celsius and without two minute averaging, which makes the data very problematic to figure out high temperatures, but people don't believe this again and demand the feed of this data from the IEM. The IEM does not have anything lower latency than what you find from the MADIS website of netcdf files. So again, we continue...
Folks still think the IEM LDM feed of NOAAPort/NWS data containining METAR/SPECIs/ CLIs/DSMs/CF6s will have lower latency and one minute updates, but it does not. These are the legacy products with much latency, on the order of minutes for the METARs to roundtrip the FAA / NWS to satellite broadcast. But the data is there and some folks think it is going to provide some magic money making scheme, so we continue...
So what the IEM has is a IDS|DDPLUS feed of METARs (^S[AP]), CLIs (/pCLI),
DSMs (^CDUS27), and CF6s (/pCF6). The METARs and DSMs are typically found in
product collectives, so the LDM product name does not contain the airport ICAO
code within the name. You have to process the collectives and find your airport of
choice within it. The IEM website does a value add of splitting these products into
airport based identifiers, but this data is not sent over the LDM feed.
So then finally after the IEM explains all this, people then ask where to find lower latency data. Goodness, yes, if the IEM knew, the IEM would be doing it already. Guess what, it does not exist. Perhaps ASOS modernization will fix this, but until then perhaps check out Synoptic Data for a feed of the FAA data that goes into the MADIS product mentioned above.
STEP 1: Send an Email
Send us an email requesting a LDM feed. You can send this email to me, Daryl Herzmann (akrherz@iastate.edu). You should include contact information and the DNS/IP of the host that you will be using to connect to the IEM LDM.
STEP 2: Configure LDM (ldmd.conf)
All local products are generated within the EXP LDM feedtype. A
nomenclature is used within the IEM to help with product routing. The general
form is: datatype routes timestamp archive_path current_path suffix
STEP 3: Sign up for IEM bulletin (optional)
You don't have to complete this step, but you can keep up-to-date with IEM news and events with the IEM Daily Bulletin. You can sign up for it here. If this service generates enough interest, I will set up a dedicated email list for it.