GIS: A Guide to File Formats

Understanding geographic information systems (GIS) is essential for implementing geospatial solutions for SaaS products. GIS can provide accurate data representation for spatial analysis, and benefits many industries including engineering, tech, utilities, and forestry.

However, there are many different GIS data file formats to understand, each with different purposes, advantages, and disadvantages.

This article clarifies how GIS data is used to solve complex problems, and the virtues of the different file formats available, allowing you to select the optimal one to capture insights for smarter data decisions.

Need support for your geospatial data integration? Get in touch with our expert GIS consultancy team. We have over 15 years of experience within the GIS sector.

 

What is GIS?

GIS is a technology that combines and maps all types of geographical data, enabling users to create, manage, analyse and understand the characteristics of a specific location(s). By connecting data to a map, integrating location data it can provide insights on a number of things such as terrain, vegetation, topography, population density, and the size and structure of human-made structures like buildings.

GIS data synchronicity allows users to analyse relationships between the various data types so one-use case is to see how natural and human-made features interact. Overlaying population density data over a terrain map can inform how geography affects settlement patterns, for example.

It can be used in a variety of projects such as urban planning, environmental management, disaster response coordination, transportation, agriculture, public health monitoring, real estate analysis, telecommunications, and geospatial intelligence. Commonly, this data is featured in map applications like Google Maps and Google Earth.

 

GIS File Formats

It’s important to choose the correct GIS file format for your project, as each of them serves a specific purpose and stores and displays its data differently. Many GIS file formats use points, lines, and polygons to visualise data on maps:

• Points can represent routes, journeys, and travel infrastructures.
• Polygons - shape-based files – can represent buildings, land use, and boundaries.
• Lines represent linear features like paths, borders, roads, rivers.

 

The most popular GIS file formats are:

1. KML

Keyhole Markup Language (KML) is an XML-based file format used to display geographic data in applications like Google Earth. It has wide compatibility, allows simple and seamless creation and visualisation of points, lines, and polygons, making it ideal for representing routes, boundaries, and geographic features in a clear and visually appealing way.

 

2. Raster

Raster format is gridded data that’s presented identically to a digital image but with spatial information accompanying it in a ‘plot raster’ – gridded cells with geographical data in each cell. The cells in a grid represent characteristics of the area covered, like elevation or temperature, and can be found in satellite imagery, land cover maps, and Digital Elevation Models (DEMs).

Raster data’s uniform data structure format allows complex spatial analyses with easy processing in high resolutions. If you’re looking for the multi-layer approach described earlier, raster data is good for this purpose. A plumbing company might use it to discover that worksites with low elevation experience water pooling during heavy rains and uncover the appropriate drainage solutions to resolve the issue.

 

3. Shapefile

Shapefile is an Esri-developed form of vector data describing the attributes of geographical features. It comes as a set of files with separate extensions.

• .shp stores the points, lines, and polygons
• .shx indexes the geometry
• .dbf stores the tabular data related to each geometry.

Shapefile is commonly used for mapping boundaries, modelling infrastructures, and analysing spatial relationships, like how close a geometric structure is to a population. They are simple and have broad compatibility, making them a widely used file format.

 

4. GeoDatabase

GeoDatabase (.gdb) is a proprietary file format for ESRI’s ArcGIS software, which stores both vector and raster data. Its efficient storage capacity and ability to process large amounts of complex data types has helped it to grow in popularity in recent years.

Its proprietary status makes it highly compatible with ESRI programs and tools, but users may find the learning curve more technically challenging and surplus for simple projects. For these, more basic formats like GeoJSON and Shapefile can get the job done effectively.

 

5. GeoJSON

GeoJSON is a text-based file format for web-mapping applications. Its text form makes it an accessible, simple-to-read GIS file format for humans and machines, making it compatible with web applications that use JavaScript libraries.

Contrarily, the text format can increase security risks as it is easier to manipulate. When it’s passing through various web applications, these risks can become a practical possibility. Although, such risks can be overcome when dealing with sensitive data by securing the transport by using HTTPS or TLS.

As a more ‘lightweight’ file format, it transfers data efficiently over the web, and unlike shapefile, stores all geometry and attributes in one file, reducing complexity. However, this simplicity makes it less efficient at handling large data volumes, for which users might experience slower performance compared with other file formats.

 

6. DXF

Drawing Exchange Format (DXF), also known as Drawing Interchange Format, is an open file format widely used in fields such as architecture, engineering, and product design. It offers seamless interoperability across various CAD (Computer-Aided Design) programs, making it easy to share designs across multiple platforms.

DXF supports 2D and 3D data, storing geometrics in vector format to ensure precision and scalability. Also, DXF is stored as a text file, making it relatively easy to edit and debug manually when necessary, though it can also be a cumbersome choice for large file sizes.

 

How to choose your GIS file format

Your choice directly impacts the accuracy of data analysis and mapping, it can also impact the performance of your solutions and the experience for your users. By selecting the right formats, you can streamline a project to deliver performant, accurate and precise results.

There are several factors to consider when selecting GIS File Formats:

1. User needs

Consider your end-user interactions. For web-based users viewing maps online or analysing data in a desktop application, GeoJSON provides better compatibility and fluidity with online mapping tools. A more technical experience – like 3D modelling or engineering - requires an illustrative file format like DXF.

If you require easy sharing across multiple platforms, then Shapefile or GeoJSON work effectively, whereas GeoDatabase is better for managing and securing complex data within the ArcGIS environment.

 

2. Project requirements

If your project involves mapping environmental developments over time, raster formats like GeoTIFF offer continuous data, allowing a more detailed and nuanced comprehension of natural phenomena that vary across landscapes. If the goal of the project is to build a map showing vector features like roads or property boundaries, a simpler file format like Shapefile or KML might be sufficient for the task.

 

3. Data characteristics

Consider the type of data you will use – whether it’s raster or vector – as well as the scale of the operation and your processing needs. Different data sets come from various sources, which determines the type of data you’re working with. Consequently, you will need a format that stores and represents this data cohesively and accessibly.

The scale of your project will play a role, too. Data that represents small areas like estates doesn’t need the same processing powers as entire countries. If your project needs pre-processing and post-processing, then formats like GeoDatabase support advanced data management features that handle this efficiently.

 

4. Technology

The computer software you’re using – whether it’s ArcGIS, QGIS, or a different platform – determines which file formats are most compatible with your project. GeoDatabase works best with ArcGIS, while Shapefile and GeoJSON are more proficient for open-source tools like QGIS.

If your project requires integration of GIS data into multiple platforms like web applications or mobile apps, a  web-mapping file format like GeoJSON is a better choice because of its seamless integration with web mapping libraries.

How your end users access and analysis of GIS data is a vital consideration, as it impacts the accessibility of your project. If you’re planning to integrate your GIS data with other applications like business intelligence tools or data management systems, then be sure to pick compatible file formats that will work with these tools most efficiently.

 

Next steps: How I‑Finity can help

At I-Finity, we create scalable solutions using a versatile range of industry-leading technologies. Our vast experience means we understand the complexities and nuances of GIS data - from file format integrations to data pre and post processing.

We can provide in-depth GIS consultation regarding your project goals, helping you to make the right technical decisions to create a solution that delivers on your data, analysis and mapping needs.

I‑Finity can support your GIS related endeavours with:

• GIS file conversion. Our in-house experts can handle the conversion of your GIS data across different formats based on your unique requirements. If you need visualised data on your web app , we can convert it into GeoJSON, or for more thorough and complex analyses, we can convert data into Shapefiles or KML or CAD. In either case, we ensure the data is in a cohesive format that displays accurately and can be easily interacted with or analysed by your end-users.
  
  
• Importing and exporting data. Our team can import and export your project’s GIS data in various formats, making it compatible with the tools and platforms your company uses. Whether your end goal is to integrate GIS data into a web application, sharing it with clients, or utilising it in specific GIS tools, we can recommend and provide the appropriate formats, allowing you to keep working with your data without compatibility issues.
  
  
• Ensuring accuracy and reliability. We will ensure your project delivers precise and reliable GIS data throughout its lifecycle, making data and visualisation consistent and easily accessible for your end-users. This will streamline your projects from end to end while maintaining the integrity and security of your data.

Contact us about your GIS project.