Not realizing how complex it is can make it seem like data just appears and updates on its own. In reality, there are world-class experts, top-notch equipment, and complex processes behind it all. But the data itself has a huge impact on many areas of life.
Geodetic system – the invisible foundation that keeps everything in place
When using a navigation app, the point marking the location seems to move by itself to where the user is going. People are often aware that satellites determine the coordinates of a device's location, but rarely think about how these coordinates are correctly placed on the map in the device. Behind this is a geodetic system – a complex framework that allows spatial points to be described numerically and displayed on a flat or spatial map.
The more accurate the measurements you want to take and the longer you want to use them, the more factors you have to consider and the more complex the system becomes. Although the Earth appears to be stationary, in reality everything around us is in motion – planets, their artificial satellites, but also continents, for example, and the locations of geodetic marks change over time. The geodetic system ensures that these changes are taken into account.
The Land and Spatial Development Board's task is to keep the geodetic system viable and ensure its usability. To this end, it manages the Estonian geodetic network (Figure 2) and a database of geodetic points, which contains a total of approximately 35,000 geodetic points (Figures 3 and 4). and the ESTPOS network of GNSS (Global Navigation Satellite System) reference stations.
ESTPOS enables both geodetic system monitoring and ultra-precise measurements, which are used in land surveying and, increasingly, in the development of self-driving vehicles and robotic mowers. This is a topic that deserves its own blog post.
Remote sensing data – 700 terabytes from the sky
The geodetic system creates the conditions for creating models with precise locations, but data must also be collected in order to actually use these models. Models can be two-dimensional (e.g., X-GIS 2.0 [land info] maps, Figure 5) or three-dimensional (Land and Spatial Development Board 3D), but the first step in creating data is collecting data from the terrain.
True, only preparations are being made in the real landscape – in Estonia, data is mainly collected using a survey aircraft. The aircraft is equipped with high-precision devices that collect data during flight. These devices also use ESTPOS reference stations to determine their location, which was one of the most important reasons for developing this network.
The three main results of the survey flights are:
- aerial photographs (photos taken directly from above, Figure 6),
- oblique aerial photographs (photos taken at an angle, Figure 7),
- laser scanning data (a point cloud describing the heights of the terrain and objects, Figure 8).
Approximately 700 TB of data is collected during a single measurement period. This requires thorough preparation: marking points are placed on the terrain (Figure 9), whose exact location is known and which simplify the linking of photos with the geodetic system; flight routes are optimized; flights are coordinated with various parties, etc. The measurements require clear skies, which means that both pilots and equipment operators are on constant standby during the measurement period.
Data collection is followed by data processing, which requires specific knowledge, software, and powerful data processing capabilities. The measurement data collected in the spring will therefore only take its final form at the end of the year. In this phase, the data collected during aerial measurement is finally linked to the geodetic system, which ensures that the coordinates of a single point measured on a map or in the terrain are the same.
Base map and vector data – an image from which a decision can be made
Data obtained from the air is in raster form, which means that it can be used as photos. However, most tasks require data in vector format – lines, points, and surfaces with additional metadata describing the object (e.g., name of a body of water, type of road surface, etc.). Vector data can be measured, visualized, analyzed, and used in automated systems.
Despite the rapid development of artificial intelligence and machine learning, there are still no sufficiently accurate automated solutions that can generate high-quality vector data from raster data. Land and Spatial Development Board is also working to increase automation, but so far we can only support mappers with analyses and checks. The final, usable result still comes from a mapper behind a special workstation.
The Estonian Topographic Database, also known as ETAK, contains vector data that directly affects landowners' rights, restrictions, and obligations. Land tax is also based on ETAK data, which means that inaccuracies cannot be tolerated. What happens in the landscape must be consistent with other registers, such as the building register, road register, or land improvement systems data. Mapping and updating other registers do not take place simultaneously, which makes keeping them in sync a challenge in itself.
Three pillars that hold the country together
The three areas described above – the geodetic system, remote sensing data, and the base map – are the pillars of Estonia's spatial data, on which a large part of the functioning of the state depends. Their impact is most visible in digital services and in the services provided by the state and local governments. State governance, the organization of administrative divisions, cadastral operations, infrastructure planning, tax calculation, national defense planning, and the organization of activities in the field – all of these depend on the existence and flawless interaction of these three pillars.
While many public services strive to make themselves invisible to users, it is still worth considering the existence and impact of these three "invisible pillars." Milk does not come from the store, and spatial data does not arise on its own.
Author: Erik Ernits, Director of Data Collection and Land and Spatial Development Board Services, Estonian Land Board
Loomise kuupäev: 14.11.2025
