The shapefile is the most famous file format in GIS, and also the most misunderstood: it is not one file but several, it has limits that surprise beginners, and it is slowly being replaced by better formats. Understanding file formats is essential for any GIS user, because the wrong format causes errors that look like data problems. This guide explains the formats that matter.

What a Shapefile Actually Is

A shapefile is not a single file but a collection of at least three files: .shp for geometry, .shx for the index, and .dbf for attributes, plus optional files for projection and metadata. All of them must travel together, and losing one breaks the dataset. Shapefiles store one geometry type per file, points, lines or polygons, and they limit field names to ten characters and file sizes to 2GB. They are old, limited, and still everywhere, because every GIS tool can read them.

GeoPackage: The Modern Replacement

GeoPackage is the modern replacement for the shapefile: a single SQLite database file that can hold multiple layers, vector and raster data, and long field names, with no 2GB limit. It is an open standard, supported by QGIS, ArcGIS and most other tools, and it is the format to choose for new projects. If you are starting a project today, use GeoPackage: it avoids the shapefile's limits and keeps your data in one portable file.

GeoJSON: The Web Format

GeoJSON stores geographic data as JSON, the same format web applications use, which makes it ideal for web maps and APIs. It is human-readable, easy to generate from code, and supported by every web mapping library. Its limits are size and precision: large datasets become slow, and it is not designed for editing. Use GeoJSON when you need to display data on the web or pass it between applications, not as your primary storage.

Raster Formats: GeoTIFF and Friends

Raster data, such as satellite imagery and elevation models, is usually stored as GeoTIFF, which embeds coordinates inside the image file. Cloud-optimised GeoTIFF is a newer variant designed for streaming over the web, so you can read part of a huge image without downloading it all. Other raster formats include JPEG 2000 and the Esri grid, but GeoTIFF is the standard, and it is what most tools expect.

Choosing the Right Format

Use GeoPackage for storing and editing vector data, GeoJSON for web maps and APIs, and GeoTIFF for raster data. Keep shapefiles only for compatibility with older systems that require them. Always include a projection file, so the data knows where it belongs on Earth, and always keep the files together: a dataset with missing parts is worse than no dataset at all. The format is not a detail, it is part of the data.

Shapefiles and the Future

The shapefile is old, but it is not dead: millions of shapefiles exist, and they will be used for years to come, because the format is simple, widely supported, and well understood. The future belongs to GeoPackage and GeoParquet, which are faster, more capable, and better designed, but the transition will take a decade. Learn both: the shapefile for the legacy data you will encounter, and GeoPackage for the new data you will create. The format is a tool, and the professional knows which tool to use for which job.

Key Takeaways

- A shapefile is several files: .shp, .shx, .dbf and more, all needed together - GeoPackage is the modern replacement: one file, no 2GB limit, multiple layers - GeoJSON suits web maps and APIs; GeoTIFF is the standard for raster data - Always include a projection file and keep all parts together

Frequently Asked Questions

What is the best GIS file format? GeoPackage for storing and editing vector data, GeoJSON for web maps, and GeoTIFF for raster data. Use shapefiles only for compatibility with older systems.

File formats are part of the data. Use GeoPackage for new work, GeoJSON for the web, and keep every part of the dataset together.