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Maps · head to head

GRASS GIS vs Nominatim

GRASS GIS logo

GRASS GIS

Maps

Long-running open source geospatial analysis engine for raster, vector and terrain processing

From
Free
Rated
-
Full reviewWebsite
Nominatim logo

Nominatim

Maps

Open-source geocoding tool for OpenStreetMap data, providing address search and reverse geocoding capabilities

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only GRASS GIS has a free tier, so it costs nothing to try first.
  • Each has a real cost: GRASS GIS the location and mapset data model requires importing data into a structured database with a fixed coordinate system before analysis, which is a real barrier for anyone used to opening files directly.; Nominatim the public API allows an absolute maximum of 1 request per second
  • They diverge on capability: GRASS GIS covers Raster analysis, Nominatim covers Core Functionality.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which GRASS GIS and Nominatim actually diverge.

Attributes where GRASS GIS and Nominatim differ
AttributeGRASS GISNominatim
Starting priceFreeOn request
Pricing modelOpen source, no licence feefreemium
Free tierYesNo
PlatformsLinux, Windows, macOSWeb

Identical on both: user rating (Not yet rated), category (Maps).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in GRASS GIS

  • Raster analysis
  • Hydrological modelling
  • Terrain analysis
  • Vector topology
  • Temporal framework
  • Image processing
  • Python API
  • QGIS integration

Only in Nominatim

  • Core Functionality
  • User Interface

What people use each for

The jobs each tool is most often brought in to do.

GRASS GIS

  • A hydrologist delineating watersheds and modelling flow accumulation over a large digital elevation modelnot Nominatim
  • A research group building a reproducible time series analysis of satellite imagery that must be rerunnable years laternot Nominatim
  • An environmental agency running viewshed and solar radiation analysis for planning assessments without buying commercial GIS seatsnot Nominatim
  • A QGIS user who needs a specific processing algorithm that only exists in the GRASS toolboxnot Nominatim

Nominatim

  • Geocoding and reverse geocoding servicesnot GRASS GIS
  • Address lookup and location searchnot GRASS GIS
  • OpenStreetMap-based geolocation datanot GRASS GIS

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

GRASS GIS

  • The location and mapset data model requires importing data into a structured database with a fixed coordinate system before analysis, which is a real barrier for anyone used to opening files directly.
  • The native graphical interface is dated and inconsistent compared with QGIS or ArcGIS, so most users end up running GRASS through QGIS and never learn the tool they are actually depending on.
  • There is no vendor, so contractual support, service levels and liability do not exist by default and must be arranged with an independent consultancy that may not cover your jurisdiction.
  • Cartographic output and map layout are weak relative to the analysis capability, meaning a second tool is always needed to produce a publishable map.
  • Module naming and argument conventions are idiosyncratic and long-standing, so scripts are durable but the learning curve is steep and transferable skills from other GIS packages help less than expected.

Nominatim

  • The public API allows an absolute maximum of 1 request per second
  • Bulk geocoding must run in a single thread and cannot be distributed across machines
  • Scripts running longer than a day or on a schedule are limited to 4 requests per minute
  • Autocomplete search against the public API is explicitly prohibited
  • Systematic queries such as grid based reverse lookups and complete data downloads are prohibited
  • Reselling geocoding results or acting as an API intermediary is prohibited
  • Every request must send a valid HTTP Referer or User-Agent identifying the application, and default library headers are rejected
  • Results must be cached client side, and repeated identical queries can lead to blocking
  • Attribution to OpenStreetMap under ODbL must be displayed

Pricing, plan by plan

GRASS GIS

Free
  • GRASS GISFree
    • GNU GPL licence
    • All modules included
    • No user or seat limits

Nominatim

On request

No published plan breakdown. See the Nominatim review.

Which should you pick?

Choose GRASS GIS if

  • You need raster analysis.
  • You want to start without paying.
  • You work on Linux, Windows, macOS.
  • You also want hydrological modelling.
GRASS GIS review

Choose Nominatim if

  • You need core functionality.
  • You also want user interface.
Nominatim review

Questions people ask

Is GRASS GIS or Nominatim better?
Neither clearly leads. GRASS GIS starts at Free and Nominatim at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, GRASS GIS or Nominatim?
GRASS GIS has a free tier; the other does not. Paid plans start at Free for GRASS GIS and On request for Nominatim.
Does GRASS GIS or Nominatim run on more platforms?
GRASS GIS runs on Linux, Windows, macOS. Nominatim runs on Web.
Can I use GRASS GIS for free?
Yes. GRASS GIS has a free tier, so you can try it without paying. Nominatim starts at On request.
What is GRASS GIS best used for?
GRASS GIS is most often used for a hydrologist delineating watersheds and modelling flow accumulation over a large digital elevation model, a research group building a reproducible time series analysis of satellite imagery that must be rerunnable years later, an environmental agency running viewshed and solar radiation analysis for planning assessments without buying commercial gis seats, a qgis user who needs a specific processing algorithm that only exists in the grass toolbox. Of those, a hydrologist delineating watersheds and modelling flow accumulation over a large digital elevation model and a research group building a reproducible time series analysis of satellite imagery that must be rerunnable years later are not what Nominatim is typically brought in for.
What can GRASS GIS do that Nominatim cannot?
GRASS GIS covers Raster analysis, Hydrological modelling, Terrain analysis, Vector topology. Nominatim covers Core Functionality, User Interface.

Answered from the vendors’ own pages

GRASS GIS: Who maintains GRASS GIS?

An international volunteer and academic developer community under the Open Source Geospatial Foundation. It originated at the US Army Construction Engineering Research Laboratory in 1982.

Nominatim: Is Nominatim free?

Nominatim is open source software built on OpenStreetMap data. It appears to be free to use, though commercial usage may require separate licensing or terms. Check the project repository or contact support for clarity on licensing.

Source
GRASS GIS: Can I buy commercial support?

Not from a vendor. Independent consultancies in the OSGeo ecosystem offer paid support and development, and availability varies by region.

Nominatim: What is Nominatim's pricing model?

Nominatim does not publish a standard pricing model on its website. As open source software, it is available for free, but commercial or large-scale deployments may require reviewing their licensing terms or contacting project maintainers.

Source
GRASS GIS: Do I need to use its interface?

No. Most people run GRASS algorithms through the QGIS processing toolbox or from Python.

GRASS GIS: Is it suitable for production use?

Yes for analysis pipelines, and it is used by agencies and research institutions. Plan for community support rather than a service level agreement.

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