FAQ Tyk Portal

Questions?

If you have a question for which you can’t find an answer here, or if have suggestions for missing features, you can mail dataservices@knmi.nl for more information.

Where are the old functionalities from KDC?

With its introduction, the KNMI Data Platform (KDP) will be more primitive and sober than the KNMI Data Center (KDC): it functions as a foundation on which we will continue to build.

This means:

  • No search option for ‘what’, ‘where’ and ‘when’
  • No filtering on Open Data
  • No WMS- and WCS-functionality

Will dropped functionalities return to the new platform? This depends on you. Our goal is to develop functionalities that are/remain used in the future.

Can I still use FTP?

No, you are no longer able to use FTP. After the migration from KDC to KDP, the way you download data has changed. FTP and HTTP downloads have been replaced by API downloads.

How can I get my open data files now?

The Get Started section provides you with the required information to access Open Data.

How do I open or use files with the .nc extension?

In KDP context, files with the .nc extension refer to NetCDF files. NetCDF is a data format that support creation, access and sharing of array-oriented scientific data.

There are different libraries in different programming languages that can be used to load and manipulate NetCDF files. Documentation of these libraries describes how to the library can be used in combination with NetCDF files.

I have lost my personal API key, what can I do?

If you request an API key, you receive a confirmation email with details for that specific API key. First, try to find this specific email in your email account. It can happen that these e-mails end up in your spam folder. Therefore, make sure your spam folder does not contain this confirmation email. If you cannot find the email containing the API key, please send an e-mail to dataservices@knmi.nl to revoke your API key. You can request a new API key after the old one has been revoked.

What happens when I go over the limits?

You will get back an error response with HTTP code 429.

Can I request a higher rate limit or larger quotas?

In most cases, developers want higher quotas or rate limits because they want to download a (partially) complete dataset. If this is the case, you can take a look at the Complete Dataset Download section.

Why does my API usage not reflect the API calls?

There might be some latency due to updating between your API calls and your API usage.

What if my key no longer works?

Anonymous keys are subject to an expiry date. Read the Get Started section for more information, and to view the latest active keys.

If your personal API key does not work, please contact dataservices@knmi.nl.

What are the costs?

All datasets in this portal are free of charge and are provided under the ‘OpenData’ policy of the Dutch government. For more information on the ‘OpenData’ policy, visit the data portal of the Dutch government.

Why are there limits?

To ensure fair usage and to be able to scale operation costs of the KDP, we limit the total number of requests you can make with an API key in a period. Unregistered users that make use of anonymous API keys share these limits among all other active users of that key. To qualify for individual limits, you can register with your personal email address. The limits that apply to your personal API key usage should be suitable for most operational use cases. If you want to download a complete dataset within a reasonable time, take a look at the Complete Dataset Download section.

What about the protection of personal information?

When you register yourself in this portal, you make use of your personal email address. Your email address is considered personal data. Personal data is information that can be used to identify you, like a name, a home address, or an email address. The protection of personal data is codified in law (‘Wet bescherming persoonsgegevens, Wbp’). This law helps to guard the privacy of citizens and is also applicable for personal data collected via the internet.

Under this law, personal data can only be used if it is explicitly stated in the user agreement. It must be clear for what purpose the personal information is stored. KDP uses your email address only for user registration and provision of access rights to datasets (authentication and authorization purposes). The law does provide some exceptions. Personal data can be used for criminal investigations if someone uses the site for committing acts or making statements which are punishable by law.

I’m not receiving the latest dataset files for a dataset?

If you view the documentation of the Open Data API in the API Catalogue, you can see that the endpoint for listing the dataset files supports the startAfterFilename query parameter. This query parameter can be used to retrieve all files after a specific filename. It makes use of UTF-8 binary order for filename comparison. If we list the files for the dataset radar_forecast/1.0 without specifying startAfterFilename, we retrieve a list of objects with the following filenames:

RAD_NL25_PCP_FM_201910261400.h5,  RAD_NL25_PCP_FM_201910261405.h5, RAD_NL25_PCP_FM_201910261410.h5, ...

To retrieve the first files on date 2020-01-01, we pass the last valid dataset filename of the previous day as a value to startAfterFilename. In this example, this will be the file with name RAD_NL25_PCP_FM_201912312355.h5. Note that the filename consists of the date, 2019-12-31, and the time, 23:55. As a suffix, this becomes the value 201912312355. If we call the endpoint for listing dataset files again with RAD_NL25_PCP_FM_201912312355.h5 as value for the query parameter startAfterFilename, we retrieve a different list of objects with the following filenames:

RAD_NL25_PCP_FM_202001010000.h5,  RAD_NL25_PCP_FM_202001010005.h5, RAD_NL25_PCP_FM_202001010010.h5, ...

Now we retrieve the datasets file “after” the given filename. The documentation of the Open Data API explains in more detail how comparison of the value startAfterFilename with existing dataset filenames works.

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