Invitation to tender: Spatial data APIs

The public sector creates a lot of geospatial data - a lot of it being open data -. These data could be useful to others, who are often not experts on spatial data. Can spatial APIs help out? That is what we wanted to find out in a testbed on spatial data APIs.

Goal of the testbed was to detect key success factors/best practices to enable more organizations and businesses to use spatial data. The tender targeted five specific research topics:

  • Research topic #1: CRS extensions for spatial APIs
  • Research topic #2: Spatial data APIs Discovery
  • Research topic #3: Spatial data API clients, ease of implementation
  • Research topic #4: Generic vs Convenience approach for Spatial data APIs
  • Research topic #5: Simple/linked data encodings for Spatial data APIs


We are happy to share the knowledge we have gained in the testbed. All findings are recorded ion Github. Read the findings and check the Github Repository
On January 20, 2022 we presented the outcome of the entire testbed in a meeting. You can watch this meeting below.

Previous sessions


The Tender

The tender document explains the various research topics we are working on. Download the tender

Note: the tender was updated on July 26 2021 with information concerning bidding on multiple research topics.


For each research topic a budget of € 12.500 excluding 21% VAT is available

Information session

On July 15th 2021 we organised an information session. The minutes of this meeting are available below. Your tender must be submitted by sending an e-mail to, addressed to Rob van de Velde, director of Geonovum.

Information Note: Tender Spatial Data APIs (26 July 2021)

This information note contains all questions received for the tender Spatial Data APIs received before the July 22nd deadline. It also contains the questions that were asked during the information session held on July 15th 13:30 CET. The session was attended by the following organizations: Datacove, BRGM, Korrai, GIS Specialisten, ESRI Nederland, Purple Polar Bear.

For all questions we have mentioned the organization asking the question and answers from Geonovum. The questions have not led to changes in the tender document. We have however added one small change to the tender document clarifying bidding on multiple research topics. The updated tender document is posted together with:,

Note: answers below take precedent over those provided in the recording.



Esri: Is there specific data the prototypes should be based on?

Answer: No. We provide data in our testbed environment but it is explicitly allowed to use other data.

Datacove: General question to the understanding on OGC API Standards - does this include STA, or is this OGC API Standard excluded?

Answer: Sensorthings API standard(STA) is not explicitly asked for in the tender, it is possible to use STA in a proposal comparing it to OGC API features in research topics “Spatial data API clients, ease of implementation” and ”Generic vs Convenience approach for Spatial data APIs”. However our main driver behind this testbed is helping Geonovum to find if, when and how to update its Local profiles of WMS an WFS which are mandatory standards within Dutch government. The comparison to their OGC successors is our main priority.

Korrai: Can we build the prototypes on data that are based outside The Netherlands ?

Answer: Yes that is very much a possibility, we provide data in our testbed infrastructure and use cases because we can provide support on these data, but if you have data of your own which can be used to answer our research questions that is explicitly allowed. We are looking for answers on our research questions related to the standards, our national use cases are only provided as examples, not the driver behind this testbed.

Datacove: Strange as a lot of the use cases depend on dynamic data, thus will be interested to see how this will be done without STA.

Answer: the use cases are not the driver behind this testbed, our questions on standards are. It is not mandatory to use the provided use cases.

BRGM: I suggest you to have a look on what the others already do with OGC API.

For example, BRGM found that SensorThings API was much more suitable to expose Observations & Measurements, and is exposing its groundwater levels that way. I would be very surprised BRO requirements being different.

Answer: This testbed is not funded by the BRO (key registry for the underground). The use case for groundwater levels is provided as an example that can be used to answer our research questions. How to efficiently expose Observations & Measurements data is not one of the research questions we have in this testbed. We have previously explored this in a 3 day hackathon on Sensorthings API in 2019 and are well aware of its capabilities.

GIS Specialisten: What is the planning after granting the assignments?

Answer: Work starts immediately after the granting of assignments on September 9th. Roughly the first month we will focus on synergy between the research topics, the second month on implementing and experimenting and the last month on writing reports. Work must be finished before the end of 2021, this is a condition for the funds we are using.

Recording of the session

The information session of July 15 has been recorded.

The answers in the Q and A take precedent over those provided in the recording.

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