Frequently asked questions

Questions

  1. Misc
    1. What's the deal with the versions? Isn't this a stable interface?
    2. Why isn't there any last version?
    3. Will the version number change frequently?
    4. How to check for new versions
    5. What does restrictions on some data mean?
    6. Do you support gzip compression of HTTP data?
  2. Products: Locationforecast
    1. Why are symbols and precipitation in other time elements than the other weather parameters?
    2. Which symbols exists?
    3. What's the difference between all these clouds?
    4. What do the model names mean, and where will I get what?
  3. Products: Sunrise
    1. What is the accuracy for the times?
    2. Sunrise doesn't return a value!
    3. What happends when it's two sets or rises (of the Moon)?
  4. Products: Radar
    1. Why can't I access the nordic radar?
  5. Products: Extremeforecast
    1. What's the meaning of phase?
  6. Examples
    1. Examples from extremeforecast:
    2. Examples from textlocation:
    3. Example of obs forecast from textlocation
    4. Example when no obs forecast are issued textforecast
    5. Example of obs forecast from textforecast
    6. Example of a English gale forecast in textlocation
    7. Example of a English gale forecast in textlocation

Answers

  1. Misc
    1. What's the deal with the versions? Isn't this a stable interface?

      The purpose of the API is to present a stable machine-to-machine interface. Nevertheless, we sometimes find shortcomings or even errors in our products, and the versions are intended to let us fix such problems without breaking compatibility

      With the versions, we can introduce version 1.1 of a product without removing or breaking version 1.0; instead, we can have a transitional period where both work, and our users can update their client software in their own good time. Versions will only be deprecated after our users have had time to update their client software.

      Adding elements/nodes to a XML format is generally considered as a compatible change so we will not introduce new versions for this.

    2. Why isn't there any last version?

      We only change the version number when there are changes in the interface, which means that you probably need to change your code anyhow.

    3. Will the version number change frequently?

      No, we try to keep the API as stable as possible. Please read the section about versions.

      All versions will be deprecated, but still working, for some period of time after an upgrade. Details about this are given in the documentation for each product.

    4. How to check for new versions?

      Check your status codes!

      The returned status code for the products will let you know if you aren't using the last one. Read the documentation for further details.

      You can also keep yourself up to date on new versions by following our changelog rss feed. See the Actions section in the documentation for the url.

    5. What does restrictions on some data mean?

      Some data referred to in the documentation is not freely available, mostly because the data is not ours. We have the right to use the data, but not to distribute them. This is marked in the documentation for each product in a section called Restrictions. Any questions regarding this issue, please contact Kristin Lyng.

    6. Do you support gzip compression of HTTP data?

      Yes. We will serve gzip compressed data of MIME types text/html text/plain text/xml if the client requests this in the HTTP headers.

  2. Products: Locationforecast
    1. Why are symbols and precipitation in other time elements than the other weather parameters?

      The XML contains two different types of data, most data are valid for a exact time and place. Temperature, cloudiness, pressure, wind are all examples of this kind of data. For these data, the from and to attributes are equal.

      Precipitation and weather symbols are computed for a period of time. It doesn't make sense to talk about how much it rains at 12:00, but how much it will be raining between 12:00 and 13:00. Weather symbols are just calculated using the other parameters (cloud, temperature and precipitation) and is mainly a way of showing many parameters in one symbol.

      Precipitation is given for set intervals (one, three or six hours), if you need precipitation for other periods, you must compute it by yourselves. Weather symbols must be computed for the interval the symbol is going to represent, you can't just add them. This is the reason why you find some periods with only symbols and no precipitation.

    2. Which symbols exists?

      A list of symbols is available here

    3. What's the difference between all these different clouds?

      Clouds are all given in percentage, which are how much of the sky is covered with clouds. Cloudiness is total cloud cover. The others are percentage of clouds in different levels.

    4. What do the model names mean, and where will I get what?

      We have three different type of models currently in use. The list underneath describes what they are and where you get them.

      1. LOCAL:This is available for Norway and parts of northern Europe. The area might change!
      2. EPS: This is only available in Norway, including Svalbard and fishing banks. It is the probability forecast from ECMWF and is available from the third day.
      3. EC.GEO.0.25:This model is global, it is also our fallback model, in case of problems with the others. The model is run at ECMWF. This model has a approximately resolution of 15 km.
  3. Products: Sunrise
    1. There are up to three minutes difference for the sun rise and set compared with the Norwegian Almanac (Almanakk for Norge). Comparison done for 2008. The difference are somewhat bigger for moon rise and set (15 minutes).

    2. The algorithm won't necessarily converge for all situations. It is known that it isn't able to compute values for high latitudes (near the poles).

    3. It might happen that the Moon rises or sets twice a day, in this case the first event will have the usual attribute of set/rise, the next event is in the attribute set_next/rise_next. Example on both two rises and sets: example from sunrise

  4. Products: Radar
    1. The norwegians radar images and composites are freely available. The nordic radar composite is not freely available. Any questions regarding rights to and use of data, please contact Kristin Lyng

  5. Products: Extremeforecast
    1. Warnings of extreme weather, extreme forecast, are issued from time to time (typical once a year). A extreme forecast have different phases, the meaning of the phases are:

      • A: a weather system looks like it might be a possible extreme forecast. The system are followed closely, but we have not issued any warnings of extreme weather yet.
      • B: the extreme weather will start in the next 12 hours
      • C: the extreme weather are ongoing
      • D: the extreme weather are over