Free GIS data: Where to find it, and how to use it

Sourcing reliable spatial data for geographic information systems (GIS) can take significant time and effort. Although geospatial datasets exist across government agencies and private organizations, they often live on separate platforms and come in different formats. 

Fortunately, free GIS data is available if you know where to look. This guide highlights some of the best free data sources and ways to know the information is top tier.

What’s free GIS data?

GIS data is location-based information that individuals, businesses, and government agencies use to create maps and analyze spatial relationships. Free GIS data sources usually refer to publicly available data that people download and use under specific licensing terms. Some free datasets are completely unrestricted, while others require attribution or limit commercial use. 

Here are a few free data formats that are typically available:

• Raster data: Covers satellite imagery, aerial photography, and elevation models
• Vector data: Represents geography using points, lines, and polygons
• Tabular data: Stores location-related attributes linked to geographic features

The most widely used GIS datasets come from government agencies that publish open data for public use. Other resources are open-source mapping projects and academic institutions, which offer geographic information on various subjects, from transportation networks to population trends. 

This information is completely raw — it shows you where something is or which demographics exist. To get value from free data, you’ll need to clean it, integrate it into GIS software, and layer it with other datasets.

Free GIS data: Types and collection methods

Free GIS data comes in various forms, and they’re all useful in different ways. Here are some free data types and collection methods to consider, so you can find what your team needs.

Types of GIS data

Let’s take a look at some common types of free GIS data.

Raster data

Raster data captures information continuously across a landscape. It stores information in a grid of cells, where each cell contains a value representing a specific characteristic.

It works well for analyzing large geographic areas and studying natural phenomena that change gradually. For instance, you can use raster data to map elevation, population density, and economic activity.

Use cases for raster data include:

• Analyzing flood risk through hydrological mapping
• Temperature and climate monitoring
• Urban heat mapping

Vector data

Vector data represents geographic features using precise coordinates, with each feature stored as a distinct point, line, or polygon. It treats features as discrete objects, delivering the accuracy and detail needed for complex planning and management applications.

Here are a few examples of vector data:

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• Points indicate specific locations, like weather stations and survey markers.
• Lines symbolize linear features, like hiking trails and transit routes.
• Polygons depict areas and boundaries, like parcels and municipal limits.

Tabular data

Tabular data organizes information in rows and columns. It provides depth, helping describe and analyze geographic features. Users can link it to spatial data through identifiers like addresses and parcel numbers, and it may or may not contain coordinates. Common use cases include analyzing demographics, logging property records, and monitoring public health statistics.

Methods of GIS data collection

Here’s a look at how most geospatial data is collected.

Remote sensing

This method collects geographic information from a distance using satellites, aircraft, and drones. Remote sensing techniques access hard-to-reach locations and offer frequent updates across broad geographic regions.

If teams connect to real-time cloud data sources, remote sensing techniques also provide continuous monitoring. For instance, disaster response teams may use this live data to track ongoing wildfires.

Surveys and ground collection data

Surveys and field data collection gather information on the ground using GIS apps, mobile mapping systems, and direct observations. Teams physically move through an area, taking photos and marking coordinates. While it usually requires more time than other collection techniques, it offers a high level of accuracy. Popular use cases include mapping property boundaries and surveying construction site safety. 

LiDAR and elevation data

Light Detection and Ranging (LiDAR) technology uses laser pulses to measure distances between a sensor and the Earth's surface. It creates highly detailed, three-dimensional representations of terrain, vegetation, and infrastructure. LiDAR supports highly accurate terrain modeling and 3D mapping. Common applications include flood plain mapping and forest canopy estimation.

5 best free GIS data sources

The following resources are widely used for open source GIS data, providing information for mapping, analysis, and decision-making:

1. OpenStreetMap (OSM)

OSM is a large collaborative mapping project. Volunteers contribute and update geographic information, creating a global database of roads, buildings, and points of interest.

Features: 

• Free-form tagging system
• Custom basemaps and styling
• Routing and navigation
• Geocoding and GIS analysis
  
  

2. USGS and government portals

The U.S. Geological Survey (USGS) and other government data portals provide GIS datasets, including elevation models, hydrography, and topographic information. USGS is a common data baseline because of its consistency and accuracy of reporting.

Features:

• Earth observations and geospatial analysis
• Natural hazard monitoring
• Energy and mineral assessments
  
  

3. NASA Earth Observations (NEO)

NEO offers free access to global and environmental climate-related raster data collected through satellite missions. Researchers and environmental analysts use these datasets to monitor conditions across the planet. 

Features:

• Atmospheric dynamics
• Surface biology and geology
• Mass change and hydrology
• Oceanography and cryosphere
  
  

4. Natural Earth Data

Natural Earth is a public-domain designed specifically for cartographic and visualization projects. It offers generalized geographic information for small-scale maps, reports, and presentations.

Features:

• Three resolution tiers
• Embedded ranking attributes
• Alignment of vector boundaries and raster layers
• Projection-friendly cartography
  
  

5. ArcGIS Hub

The ArcGIS Hub connects users to multiple open data portals. It connects users to data and maps uploaded by governments, nonprofits, and universities. 

Features:

• Interactive web maps and graphs
• Data sharing in multiple formats
• Federated catalogs
• Dynamic APIs

How teams use free GIS data

Here are some of the real ways people use free GIS datasets:

• Urban planning: These teams use GIS data to evaluate land use, zoning regulations, and transportation networks. By referencing multiple data sources, they can identify development opportunities and assess future infrastructure needs.
• Environmental analysis: Researchers reference raster data and satellite imagery to track changes in land cover and climate conditions. These insights help organizations manage natural resources and support conservation efforts.
• Site selection: Businesses rely on spatial data to find locations for retail stores and warehousing facilities. Teams analyze factors like demographics, accessibility, and market demand to compare sites and determine trade areas.
• Logistics and mobility: Analysts turn to GIS data when assessing routes, travel patterns, and service coverage. For example, a fleet manager might visualize traffic congestion and infrastructure when optimizing truck routes.

How to evaluate free GIS data

Here are a few ways to evaluate free GIS data before your next project.

Data quality and accuracy

When reviewing a dataset, consider the source, collection method, and location accuracy. A transportation dataset with outdated road information could affect routing analysis, while inaccurate property boundaries might lead to planning errors. High-quality GIS data ensures maps and models produce trustworthy results.

Resolution and scale

Resolution describes the size of each pixel in a raster dataset — smaller pixels capture finer details and larger pixels cover wider areas with less detail. Meanwhile, scale determines how accurately features reflect real-world locations and dimensions in vector datasets. There’s no “best” size — selecting the appropriate resolution and scale for your project provides accurate results.

Update frequency

Update frequency impacts how useful a dataset is. Geographic information changes as roads are built, businesses open and close, and environmental conditions evolve. Check when the data source was last refreshed and how often new data becomes available to ensure you’re working with fresh insights.

Licensing and usage rights

Free GIS datasets don’t all have the same usage permissions. Depending on the provider, they may allow unrestricted use, require attribution, or limit redistribution. Take time to review licensing terms and data-sharing permissions to comply with each organization’s policy.

Bring your GIS data into one platform with Felt

While there’s a wealth of free data available, it’s only valuable if teams can layer it, analyze it, and share it. Felt brings your workflows into a single cloud-native GIS platform, making it easy to connect cloud sources — like Snowflake, BigQuery, Redshift, Postgres and Databricks — and import multiple datasets with a few clicks.

Felt lets you layer and visualize data, then share the resulting maps with stakeholders. Toggle layers, apply filters, and run spatial analysis. Then, send the results to your team and collaborate before you publish your map and show your findings.

With Felt AI, teams delve into data even faster. Ask questions in natural language to visualize, analyze, and extract insights in seconds.

‍Start your free trial on Felt to layer, analyze, and share your GIS data, or connect with our team to see Felt AI turn those questions into insights automatically.