Area value in cadastral data

You might encounter slight variations in the reported area for the same parcel. This article explains the reasons behind these differences and clarifies how to interpret the area values in Glint.

Why Different Area Values Appear in Glint

Despite digitalization, several factors can influence the reported area of a parcels [1]:

Survey Accuracy: The quality and methodologies used in historical cadastral surveys can impact the recorded area accuracy.
Map History: Maps may be altered over time through stretching, redrawing, or digitization, introducing inconsistencies.
Map Projections: Different map projections and the width of their zones can cause slight distortions in area calculations.
Coordinate Reference Systems (CRS): The quality of the national CRS and how data is transformed between systems can influence area values.

Understanding "Official Area" and "Area" for parcels in Germany in Glint

When you view a German parcel's details in Glint with the parcel data layer enabled, you will see two area values:

Official Area: This value comes directly from the official cadastral record for the parcel and may originate from historical surveys dating back to the 19th century [2]. (For an example in Hessen, Germany, see: Behebung von Flächendifferenzen | HVBG [2] - website in German)
Area: This is the geometric area calculated using the parcel boundary points projected into a specific CRS (EPSG:32632). This is the area value used for sorting and filtering in the “Parcel search” window.

Impact of "Copy Polygon to Project" Button

The "Copy polygon to project" button in Glint creates a polygon based on web map tiles [3]. Since these tiles use the Web Mercator projection (EPSG:3857) and may simplify the geometries at lower zoom levels, this process might introduce minor area variations compared to the "Official Area" and "Area" values, although not more than a few percent.

Are Glint's Area Values Legally Binding?

It's important to remember that the area values presented in Glint are approximations and should not be considered legally binding. Only a professional land survey can provide precise and legally defensible measurements.

Citations

[1] Berk, Sandi, and Miran Ferlan. "Accurate area determination in the cadaster: case study of Slovenia." Cartography and Geographic Information Science (2016).

[2] Hessische Verwaltung für Bodenmanagement und Geoinformation. "Behebung von Flächendifferenzen | Bodenmanagement Geoinformation." https://hvbg.hessen.de/ (Accessed April 3, 2024).

[3] Wikipedia. "Tiled web map." https://en.wikipedia.org/wiki/Tiled_web_map (Accessed April 3, 2024).

Additional resources

For requests regarding data layers, see this article for details of the best person to contact at Glint.