Please note: The algorithm descriptions in English have been automatically translated. Errors may have been introduced in this process. For the original descriptions, go to the Dutch version of the Algorithm Register.
ChangeMapp - change in the outdoor space
- Publication category
- Impactful algorithms
- Impact assessment
- Field not filled in.
- Status
- In use
General information
Theme
- Space and Infrastructure
- Traffic
Begin date
Contact information
Link to source registration
Responsible use
Goal and impact
The province has a legal responsibility to keep (parts of) the Basic Registration of Large-Scale Topography (BGT) up to date and organise proper management and maintenance of its infrastructure. The ChangeMapp algorithm helps to keep the BGT and the overview of the infrastructure to be managed up to date, while showing that this information is current. From 2024, in the ENSIA BGT self-assessment, regulator BZK asks for the deployment of mutation detection. The aim is to make mutations (changes) in outdoor space easier to detect. Have there been changes to structures (BGT/BAG) or changes in grey/green/blue objects (BGT)? Have dormers (WOZ) and solar panels been installed? With ChangeMapp, we get a geographical or administrative file with the relevant changes, or mutations, compared to the current BGT, BAG or WOZ.
Considerations
The algorithm is an efficient way to compare the 'outside world' with the 'data inside world'. Other methods considered are more labour- and/or cost-intensive. Other methods include manual image tracing, LiDAR scan cars, data reacquisition, and sampling regimes. The disadvantages are minimal because the results are not directly processable and thus always require human assessment, no personal data are processed, and only public sources are consulted.
Human intervention
The algorithm produces a geo-file, which is reviewed by data managers from the provinces. The algorithm does not make any adjustments itself, nor does it make concrete suggestions for adjustments, but only identifies locations with a potential mutation. Data managers then collect the missing data on a regular basis and update the relevant data with it.
Risk management
The legal and ethical risks are limited because the results cannot be processed directly and therefore always require human assessment. No personal data are processed, and only public sources are consulted. The algorithm is used additionally to existing practices, so it is not heavily relied upon. The regulator also encourages the use of mutation detection, which shows the limited risk. Other risks are not seen.
Legal basis
The algorithm is mainly used for the Large-Scale Topography Registration Act and also indirectly for the Roads Act. The BGT Act requires the province to keep the BGT map up to date, and the Roads Act requires the province to maintain its roads.
Links to legal bases
- BGT: https://wetten.overheid.nl/BWBR0034026/2024-01-01
- Wegennet: https://wetten.overheid.nl/BWBR0001948/2024-01-01
Operations
Data
Information from public sources: the Basisregistratie Grootschalige Topografie and aerial photos from Beeldmateriaal Nederland.
Links to data sources
- PDOK: https://www.pdok.nl/introductie/-/article/basisregistratie-grootschalige-topografie-bgt-
- Beeldmateriaal NL: https://www.beeldmateriaal.nl/
Technical design
The algorithm uses image processing to compare aerial photos with an existing BGT dataset and provides possible anomaly points in a GIS file for human assessment. The algorithm is not self-learning.
Aerial photos are analysed and the application indicates by means of a colour area on the photo where mutations relative to the map have taken place. The results of ChangeMapp are baseline measurements, alerts and/or mappings of objects relevant for the BGT, BAG and WOZ. These are delivered as geometric files (e.g. Shapefiles), administrative files (e.g. Excel) and work projects (e.g. QGIS projects). The current scope of objects handled is:
- Signalling and mapping of structures against the BGT, BAG or composite map of structures.
- Signalling of grey/green/blue objects with respect to the BGT.
- Zero measurement and/or indication of dormers compared to the WOZ.
- Zero measurement and/or signalling of solar panels compared to the WOZ or another reference file.
The results are provided with several attributes such as classifications and other object properties.
The province only uses the BGT side of the algorithm and is an (optional) part of the regular data quality processes of the province's BGT data managers.