Sorting out the National Weather Service XML feed

Tuesday, June 3, 2008, 12:19 PM
Website Design by John

I was tinkering yesterday with building a 7-day forecast from the data that can be had off the National Weather Service XML feeds. Let me tell you this: those feeds are frakkin cumbersome. Wow.

First off, the NWS feed is built to work with their own code using PHP/SOAP. Which, hey, I have nothing against, but not if that is all the feed is built to do.

The NWS is typical of what is wrong with a lot of government open data projects. Now, it isn't as poorly designed as the FCC's database -- because that was built to just be a pain, because you have to POST your request in before you can get the data. On the other hand, once you get the data out, the FCC's system is dead easy, since you can pull it all into an XLS or CSV format and from there do whatever you need to export it to database.

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The NWS data is not only inconsistent, the keying on it is inconsistent. Hahaha.

Check it out, here:

Depending on how many hours of data the NWS has, the keys for the data change. But, it doesn't note which pieces of data the keys actually go to. So, for example, there maybe 57 pieces of data for the Dew Point that day, and it will correspond to one of the k-Xh-Xn keys. But, it only matches the keys to hours and and days in SQL format + GMT deviation.

So, you actually have to demuck from the feed how long the strings are for the data you want before you can match them to a key and thereby to a day.

For example, in order to pull the hourly predicted temperature, you have to find the XML category for that, identify it, load all its data into an array, and then count them. You also have to load all the keys for all the data. And you have to put them in an array and count those, too. And then you have to create your key-to-data matches by matching the counts against the key of the same length.

I don't have a problem with doing that. But, holy shit is that a lot of effort to get at what is supposed to be easily publicly available data!!

Some point here I will clean up the code and post it here. If someone has a strong interest in it,
use the contact page and I will post it.

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Wonder where to start with your web design business?

This blog follows along with my efforts to build and grow a website design business, Pro Content and Design.

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Good luck, and happy reading.

Thank you,
John Crawford
Pro Content and Design