Every soil investigation includes a site plan showing boreholes, monitoring wells and boundaries. For many soil professionals, this is the only use they make of GIS. Some do not use it at all.
The main barrier is the complexity of GIS software. Packages such as QGIS and ArcGIS offer many possibilities but take time to learn. In many teams, GIS knowledge sits with one or two colleagues. Anyone who does not use it regularly has to relearn it each time.
Yet GIS adds value at every stage of a soil investigation: a better-founded investigation strategy, faster insight into the delineation of contamination, and one consistent picture for the field team, project manager, consultant, client and competent authority. WebGIS applications have also lowered the barrier to entry.
This article explains why location is the connecting factor in soil data, which ten practical GIS applications you can use at each project stage, and what you need to work with up-to-date TerraIndex data in GIS.
Prepare better
Combine site history, boundaries and environmental information in one investigation plan.
Assess spatially
Identify patterns, measure distances and determine where additional investigation is needed.
Share consistently
Use one map for the field team, consultant, client and competent authority.
Soil data are location data
Almost all data from a soil investigation are tied to a location. Yet they are often assessed in borehole descriptions, assessment tables and reports, with coordinates in a separate column. You then have to infer the relationships between measurement points, possible sources and the surroundings yourself.
“The challenge is no longer collecting, but connecting. Workflows are organised around who, what and when. The where is only added afterwards, if at all.”
A single borehole is a collection of measurements. Combined with nearby boreholes and environmental data, such as the Dutch Key Register of the Subsurface (BRO) or Natura 2000 boundaries, the same borehole helps answer practical questions. Is the site suitable for construction? How much settlement can be expected? Can excavated soil be reused elsewhere?
GIS adds three important functions:
| Function | Application in soil investigation |
|---|---|
| Visualise | Show exceedances on the map and immediately see where a potential problem lies. |
| Combine | Bring together boreholes, soil quality classes, cadastral boundaries, Dutch KLIC utility information and other sources spatially. |
| Analyse | Answer spatial questions that no single source can answer, such as how much soil will be excavated in each quality class. |
For many applications, you need only a limited part of GIS functionality: loading map layers, filtering, measuring and colour-coding results. To start without extensive training, you can choose a webGIS designed for professionals without a GIS background, such as Onemap by GeoSquare.
10 practical GIS applications by project stage
Below are ten applications organised by the stages of a soil investigation. Each explains which question it answers and which data you combine.
GIS in soil investigation preparation
Use historical information to substantiate potentially contaminated areas
Filled-in ditches, former underground tanks and demolished industrial buildings are often no longer visible but still determine the investigation plan. Overlaying historical maps, aerial photographs and boreholes from earlier investigations on the current situation helps locate potentially contaminated sublocations accurately. The drilling plan then directly reflects the preliminary investigation.
Define the investigation strategy spatially
The number of boreholes, monitoring wells and inspection pits depends on the area and suspected contamination of sites and sublocations. GIS lets you measure these areas and see suspect areas, investigation boundaries and groundwater data together. You can develop an investigation strategy under Dutch NEN 5740 or NEN 5707 that is spatially sound and draw the planned measurement points directly on the map.
Prepare safe and feasible fieldwork
Dutch KLIC utility information shows cable and pipeline locations in advance, including pipelines requiring additional precautions. Parcel boundaries reveal whether a measurement point falls outside the client’s site and requires additional permission. Where relevant, include information on unexploded ordnance. The field team receives a drilling plan that is both technically sound and practically feasible.
GIS during fieldwork
Assess the implications of moving a borehole
A borehole cannot always be drilled at its planned location, for example because of paving, buildings or utilities. Moving it a few metres can affect the investigation. When actual surveyed boreholes appear directly on the map, the project manager or consultant can immediately assess whether the suspect area is still sufficiently covered or an additional point is needed. A shared map of suspect areas helps the field team make the right decision on site.
Assess and analyse results in GIS
Assess results spatially
The map shows whether an exceedance is isolated or part of a pattern. You can assess whether contamination has been sufficiently delineated and whether clean boreholes are close enough. Filtering topsoil and subsoil helps determine whether further analyses of existing samples suffice or additional boreholes are needed.
Measure distances and areas to inform next steps
GIS measures the distance between an elevated result and the suspected source, and provides an initial estimate of the area of a contaminated zone. Combined with a known layer thickness, this indicates the volume. These measurements support further investigation design and an initial remediation cost estimate.
Filter for what matters to the investigation question
At larger sites, a map showing all data quickly becomes cluttered. Filtering lets you use the same dataset for different questions without rebuilding the map each time. For example, you can:
- show only monitoring wells or only boreholes;
- view results for a single parameter, such as zinc or PFAS;
- show only exceedances of a particular class;
- select measurement points within one sublocation;
- view results from a specific soil layer.
Work at different scales
In GIS, you can switch between the entire project area, a sublocation and an individual measurement point. The same map provides an overview for the project manager, detail for the field team and a basis for reporting.
GIS in reporting and advice
Consult sources in one environment
Historical maps, cadastral parcels, Dutch KLIC utility information, elevation data from the Dutch AHN, groundwater data from BRO and earlier investigations are often available as map services. In a single GIS environment, you can consult them alongside your own investigation data without constantly switching between PDFs, files and websites.
One map for internal discussions, the client and competent authority
The map used to assess a site also supports your conclusions. Internally, it explains why an additional borehole is needed. For the client and competent authority, it shows where contamination was found and how it is distributed across the site. Measurement points, results and boundaries are already available for the final report.
TerraIndex data in GIS: export or connect directly
For these applications, GIS data must reflect the current state of the investigation in TerraIndex. There are two ways to do this.
Export and import. Export coordinates and results from TerraIndex and load them into your GIS package. This works, but an export is a snapshot. After every change, create a new export and replace the map layers. If several colleagues work on the same project, you must also keep track of who is using which version.
Connect directly with the TerraIndex GeoServer. GeoServer makes TerraIndex data available as GIS map layers through WFS. TerraIndex remains the central source, and changes are reflected in the layers without repeatedly creating new exports. Available data include:
- field data for the actual surveyed measurement points;
- assessment results, filterable by layer and by topsoil or subsoil;
- project boundaries;
- sublocation boundaries.
| GIS environment | Suitable for |
|---|---|
| Onemap by GeoSquare | Teams without a GIS specialist that want to start spatial work quickly using their soil expertise |
| QGIS | Organisations with an existing open-source GIS workflow |
| ArcGIS | Organisations already using Esri |
| Other GIS software | Applications that can read WFS services |
Want to know exactly how the connection works? Read What is the TerraIndex GeoServer?
Free trial connection using your own TerraIndex projects
Want to assess what a direct GIS connection can add to your workflow? Test it with your own TerraIndex data.
With a free, no-obligation trial connection, your current projects become up-to-date map layers in Onemap, QGIS, ArcGIS or other GIS software supporting WFS.
- Request the trial connection.
- Jeroen ten Kate, account manager at TerraIndex, will contact you personally to discuss the connection.
- Start working with your own projects and discover what GIS can bring to your work.
Request a free trial connection ➔
Missed the webinar? Watch the recording, in which Bram Ardesch and Jeroen ten Kate from TerraIndex and Maarten van der Hoek and Wilbert van Dorremolen from GeoSquare demonstrate the connection in practice. Watch the recording
Source
- Dutch Geological Survey, Ondergrond in beeld, accessed on 17 September 2026.