Building footprints are transforming multiple industries – here’s how

Building footprints display the outline of individual structures on a digital map. These simple representations of the exterior shape and area of a building can have a profound impact on how multiple industries work. 

At a glance:

• Building footprint polygons show the outline of individual structures on a map
• A building footprint map can be used to inform decisions in multiple sectors
• Find out what building footprints are, and how they’re produced
• Learn about key use cases – from urban planning to telecoms to policymaking and more

When you open up a map on your smartphone to find your way around town, you may well have noticed building footprints outlined in these applications. They often appear as gray squares or rectangles and show roughly where stores, restaurants, or other landmarks are. This makes them really useful for wayfinding. 

While the building footprints provided by major device manufacturers are very useful for consumers, their value for businesses and the government can provide great value as well. In recent years, building footprint data has become ever more accurate, and this is revolutionizing how multiple industries plan their operations and deliver services. Let’s see how your organization can benefit.

What are building footprints?

In terms of digital mapping, a building footprint is simply a polygon on a map that represents the physical outline of an individual structure (drawn along the exterior walls). GIS building footprints are represented as 2D shapes on a digital map, and can be added or removed as a vector laye.

The polygon itself is useful in that it differentiates an individual building from its surroundings (trees, gardens, roads, parking lots and other structures…). However, it is when this is joined up with other data sources that it becomes really powerful. 

If you look at the ‘raw’ satellite image of an urban area, the human eye can fairly quickly identify roads, greenery, and buildings. That’s helpful, but it doesn’t really help answer complex questions:

• Precisely how many buildings are on a street? 
• What type of buildings are they (e.g. residential or commercial)? 
• What might the buildings be made from? 
• Are they formal or informal dwellings?
• How tall are the buildings?

And this is where building footprint GIS data help. By identifying individual structures, you can start to do much more advanced analysis.  

Building footprint vs building area

Sometimes, people use the terms building footprint and building area interchangeably. However, there are some important differences. 

As mentioned above, a building footprint is a polygon used in GIS maps representing a building’s location in its environment, its dimensions (shape) and the ground surface it covers as measured at the exterior walls. 

On the other hand, ‘building area’ is a more general term and can mean different things in different situations. In real estate, a building’s area is often used to describe total internal floor space (including on all floors/levels) of the building. In other industries (e.g. architecture), building area may denote area as measured at the exterior walls. Building area is usually measured in square feet or meters.

Introduction to building footprints in GIS

In GIS mapping, building footprints can really help to analyze and understand a place. They are usually represented as vector data, allowing you to add or remove them as a layer in your map. In this section, you’ll learn more about GIS building footprints, how they’re made, and where the data comes from. 

How is a building footprint polygon made?

There are three principal ways of getting building footprint polygons onto a map:

• Ground surveys: This is, arguably, the most accurate method building footprint mapping. A team of mappers physically visits a site and plots the exact dimensions and location of a building onto the map. Since the mapping team can verify the building layout with their own eyes, the issue of false positives (e.g. incorrectly labeling a car park as a house) is avoided. But of course, ground surveys are extremely time-consuming. 
  
  
• Drawing onto satellite images: As satellite imagery has become ever more accessible through various open source initiatives (such as Microsoft mapping), it’s become ever easier for individuals and companies to manually draw out building footprints on satellite images. This has allowed many more buildings to be mapped out and is a big advance. Still, this is a manual method (you literally draw around the outline of individual buildings onto a map), so it takes up a lot of time. 
  
  
• Deep learning: Today, specialist mapping companies are using deep learning technology such as semantic segmentation  to accelerate the creation of building footprint polygons in more places, faster. It’s now possible for an algorithm to identify buildings automatically with a similar level of accuracy to the human eye. The deep learning approach is especially helpful because it can support change analysis (i.e., comparing how land use has shifted over time to see if buildings have been demolished or new ones built). At LuxCarta, we have developed a range of high-resolution building footprint extraction techniques using machine learning - read about them here. 

Sources of building footprint data

There are several common sources of building footprint data. These include :

• In-person observation and measurement
• Open source data, particularly OpenStreetMap
• Microsoft Global Footprint
• Google Open Building
• Drone images
• LiDAR mapping
• Satellite images
• Purchasing readymade building footprint libraries from specialist providers

Beyond footprints: 3D mesh building extraction

What can you do with building footprints?

On its own, a building footprint polygon might not seem particularly revolutionary. However, when you match it up with other data, these simple squares, rectangles, and triangles can be incredibly powerful, unlocking enormous amounts of value.

Building footprints can help a huge range of industries. Here are just a few building footprint examples in different industries :

Radio Frequency planning

Telecoms firms can benefit enormously from accurate building footprint maps. If, for instance, they are planning to roll out 5G networks, they need to know about the density and height of buildings in a specific area (as well as other obstacles such as trees and topography). This information can help identify the best location for cell towers.  

Fiber deployment

A building footprint can be used to determine the priority or highlight strategic areas for deploying fiber to the home (FTTH) in large residential and commercial areas. This is because the size and layout of an accurately captured building can impact the feasibility and cost of installing fiber optic cables. For example, a building with a larger footprint may require more extensive and costly excavation work than a smaller one Additionally, buildings with a larger footprint may have more potential customers or tenants that would benefit from access to high-speed internet. Overall, analyzing building footprints can help service providers to identify areas where it would be most cost-effective and beneficial to deploy fiber optic cables.

Local government

A map showing building footprints can be invaluable to local government. For example, a town or city’s urban planning department can use the map to identify areas with high or low building density, to inform them where to build next. Meanwhile, local government can also use this information for planning services – from where to install electric vehicle charging points to street lighting or frequency of waste collection. 

Insurance

The insurance industry can also benefit from detailed building footprint data fiber to the home (FTTH) in large residential and commercial areas.to carry out risk assessment. Accurate maps can help them identify nearby risks (e.g., rivers, fire risks) and use this to inform their insurance quotes and premiums. 

Property development

By analyzing building footprint maps, property developers can rapidly identify new opportunities for residential or commercial sites. For example, looking at building footprint data, they might identify brownfield sites or vacant lots that have great potential, without having to physically visit them in person. It can also be useful for things like ecological surveys, which are part of the planning process in many countries. 

Architecture

There are many uses of building footprints in architecture. They can help demonstrate how a planned building/street/neighborhood will integrate into the surrounding landscape, support zoning and planning requirements, or help with risk assessment (for things like flooding).

Central government

National governments and policymaking units can use building footprints to improve any number of services. For instance, by cross-referencing population maps  with  building footprint polygons, they might be able to deliver targeted poverty relief schemes. Meanwhile, in many countries, a lack of data on addresses makes collecting income tax a challenge – but building footprint polygons can help locate property and ensure everyone pays their fair share. 

Retail, logistics, and marketing

Building footprints are also incredibly useful to a range of commercial businesses. They could be used by convenience store chains to identify where to open their next branch, by food delivery firms to map out routes, or by sales and marketing departments to choose billboard locations or direct marketing campaigns. 

Solar energy businesses

Rooftop solar energy firms can use building footprints to help identify locations and orientations when choosing where to install rooftop solar arrays. 

Disaster recovery

Building footprint data has also proven incredibly helpful in disaster recovery and aid scenarios following earthquakes, floods, or hurricanes. The information provided by this data helps aid agencies figure out where buildings and people are located, how to get help to them, and also with rebuilding after the event. 

Learn mapping: What is a digital surface model?

How will building footprints transform your industry?

Building footprint polygons provide an incredibly powerful tool for analysis, planning, strategy, and operations in multiple industries and sectors. What is more, when combined with other data (such as 3D maps, census data, mobility information, etc.) they provide even greater richness and insights. 

Want to see how building footprints could help you? LuxCarta provides some of the most advanced building footprint data and maps in the industry. Contact us today for a demo.