Reducing Rework in Civil Design Using Premium Aerial and Satellite Imagery

Studies show the cost of rework in civil engineering projects is typically 5-15% of a project’s total cost, and can in some cases reach even 35%. As a civil engineer and CAD manager designing projects such as sanitary landfills, I found customers, contractors, and stakeholders asking for changes regularly. Then one project forever changed my tolerance of rework, and exposed the root of the problem: an incomplete understanding of real-world project site conditions, even after surveying.

In this article, you will see how a tool created to use Google Earth in AutoCAD has developed into a powerful platform, giving users access to high-resolution and up-to-date aerial and satellite imagery from the world’s premium image providers. See how in the early stages of projects such imagery helps you make better and faster design decisions, speeding workflow and gaining greater insight and confidence while reducing the waste and cost of rework.

The construction industry is notorious for tight profit margins, with companies bidding low in hopes of making their income from profitable ‘variations’ or add-ons. When Construction News analyzed the top 10 biggest UK contractors in 2017, they found that they registered "an average pre-tax loss of -0.5%.” That sounds dismal, but what if variations and add-ons were not suppressed by the dreaded rework, which costs your company money?

The value of removing rework—fixing mistakes or revisions—could easily affect your company’s total income per project, even without taking into account costs such as the damage to business and personal relationships, or to morale and reputation. Eliminating rework may sound impossible, but here’s an important point: an Autodesk Construction Cloud blog post cites that as much as 70% of total work encountered during construction and engineering projects results from design-induced rework.

Reducing Design Error Rework Is Essential to Your Company’s Profitability

When rework happens, you can almost always look back with hindsight and say, “This could have been avoided.” I have a personal looking-back story that I often tell, because it became a life-changing event for me, and changed the workflow for thousands of engineers across the world. What happened was a topographical survey that simply didn’t match reality, as the project was in a beautiful part of Greece with steep ground and dense vegetation difficult to pass through. From the surveyor’s viewpoint, there was no reason to assume the hard-to-access center of the parcel was in any way different than its perimeter.

Project area
Reality didn’t match a guesswork survey in the area circled in red. This discrepancy wasted four months, and over 10% of total budget. Image ©2020 Google.

This, combined with a late or non-existent cadastre (another common feature of rural Greece), led to the shock of later discovering a local shepherd had built a small structure to keep his sheep right in the middle. When word of the disaster reached me, my first reaction was to look in disbelief at Google Earth, which was a new service at the time. There it was, a tiny house, clearly visible from above, but entirely invisible from the parcel perimeter. As tearing down the building was not an option, this meant a major redesign of everything in that area, in order to build around it.

I recall the numbers all too easily. A €6 million project, with total rework costs over €600,000, because guesswork had created rework. Such a waste. Hindsight is great, as is Google Earth, so that event led me to use my passion for coding software to bring AutoCAD and Google Earth together. It was far too fiddly and time-consuming to make flat photographs of our curved world line up with each other manually, so I needed to create software to allow for the Earth’s curvature and elevations. Then I had to allow for over 3,000 map datums. It became quite a project.

The real world is curved and photos are flat.
The real world is curved and photos are flat, so I developed software that could do in seconds what once took hours with Photoshop or sticky tape.

A picture is worth a thousand words because it can give almost instant understanding and insight. Having this software was so useful—and such an advantage over our competition—that it felt like cheating. We could:

  • See the area, to scale and inside AutoCAD, enabling us to instantly reply to clients with our design ideas, or to identify any issues.
  • Create initial sketches so good they were often the final project.
  • Show the client our plans as 3D models inside Google Earth itself, a feature still winning contracts today.
  • Design quicker and with confidence, and rework (which used to be a routine expense) became rare.

Ultimately, this led to bundling all the features into a software product we called Plex-Earth, to help our fellow engineers across the world. Plex-Earth has been successful beyond my dreams, and what follows is what we’ve learned from over 10 years of assisting engineers and architects, and where we believe things are going with photographic GIS for AEC.

Yes, Drones Are Coming, Too Slowly

The future for drones in AEC is exciting, though recent years have shown there is a growing demand for safety and privacy restrictions for these magical machines. Such restrictions will only get tighter as drone delivery services claim airspace corridors. Areas near airports or sensitive sites have already been completely banned to drones, even for commercial license-holders. Camera-drones can help you quickly spot mistakes you’ve already made, and rework is usually cheaper the earlier any errors are caught, so it’s great to see them developing.

Overall, drones have a great future in AEC and at Plexscape we’re already moving toward a drone element of the Plex-Earth platform. However, for looking around a project area and its surroundings in the very early stages of construction, using drones is too slow, and likely to get even slower over time. They are slow because where drone flights are allowed there are still permits and insurance required for professional use, which can take weeks to arrange. That is on top of the time to visit the site, fly around to collect the imagery, and then process it to be used in scale drawings. Contrast that with the way Plex-Earth imports detailed, updated imagery, already in your AutoCAD, already scaled and already aligned, in a matter of moments.

The Ultimate Aim Is to Avoid Mistakes in the First Place

Conceptual and preliminary periods are the most important stages of civil engineering projects, and when all the big decisions are made. It’s also true that early stages are when the biggest mistakes are made, so not the time to rely on your imagination or old fuzzy photos. Satellite and aerial photos can instantly show you such basics as:

  • Terrain slopes, valleys, and other physical features
  • Proximity to main roads and junctions
  • The type of roads (important for trucks or coaches)
  • Proximity and direction to public transport
  • Suitability of the area for the project

There’s no doubt that the best way to avoid mistakes is by viewing and understanding your project area, before you even start. As different projects will each have their own needs, and each project area is unique, what to look for or look out for will vary. Such variety also means that clients tell us that seeing the area from above gives inspiration for their designs.

Photos Must Be a Clear and Current View of Reality

Actual imagery is always better than relying on imagination, unless the image is out of date. Both Bing and Google provide their images to find nearby shops or in-car navigation, rather than as tools for engineers. As such, they both tend to concentrate on already heavily-developed urban areas. In less-developed areas, Google is often a year or more out of date, and Bing can be worse. Happily, other companies exist that supply updated aerial and satellite imagery. The problem has been that such commercial image providers usually demand a big, long-term, and restrictive contract with the end-user, usually large corporations or governments.

This business model is not well-aligned for AEC, as our industry needs quick access to relatively small areas, plus we need a different area for every new project. Those big companies normally deal with very big areas, or a pay-per-view model unsuitable for the workflow of AEC professionals. What they offer us in AEC is too valuable to give up easily though, so we approached them anyway. We insisted that we be able to offer:

  • A variety of payment options at an affordable rate
  • Unrestricted access to whatever images they need
  • Legal usage rights wherever possible

With literally thousands of engineers and architects around the world already using Plex-Earth, we were in the perfect position to create a true win-win situation for everyone, and some great deals have already been made. Some providers are best for high-resolution images, while others are known for their recent images. Some are best for worldwide coverage, others may give the best coverage for urban areas. At Plexscape, we offer:

  • Airbus
  • Maxar
  • Nearmap
  • Hexagon
  • Google Maps

We can also let you import Bing and other terrain mesh data.

A complete view of your project’s 3D terrain, imported and aligned for you, inside your AutoCAD.
A complete view of your project’s 3D terrain, imported and aligned for you, inside your AutoCAD.

Peeking at the Date (or into the Past) Can Help

Some of our providers will provide the exact date the image was taken, and some can even let you select earlier dates, letting you look back over time. This allows you to see trends and changes, or a lack of change, which can be incredibly helpful. This is especially true in any areas where there is moving water, as it can erode beaches or banks quickly, changing course or completely changing the landscape.

Before and after satellite images of Brazil’s Brumadinho dam disaster area in 2019.  Image © 2019 Bird.i.
Before and after satellite images of Brazil’s Brumadinho dam disaster area in 2019.  Image ©2019 Bird.i.

Proving You’re Proactive Wins Contracts

Truly understanding the project area and so avoiding errors in the first place goes beyond saving money from rework, because it can help you win the contract in the first place. Being able to show you’ve really “done your homework” instills confidence in your client, and that’s the key to having your proposal accepted and your designs approved. Some “homework” examples include:

  • Which angles will create the best views of your project, and which are best avoided?
  • Which angles will provide the best views from your design, such as a great view of a nearby landmark?
  • Could your design actually become a famous landmark itself?
  • Are there any other possible interactions, good or bad, with other points of interest or terrain features?
  • In general, how will your design really fit into its real-world surroundings?

Plex-Earth 5 lets you export your 3D models into Google Earth. From there you can create a virtual tour, literally letting clients look out the window and see the view from your design.

Design in current environment
Showing clients how new construction will blend with the environment in real life is a big selling point, and clients tell us it really helps at later stages too, such as getting local government approval.


Now in its fifth generation, Plex-Earth has evolved into a powerful platform, bringing you the latest and greatest imagery available, through partnerships with the best satellite and aircraft operators in the world. It’s a genuine milestone in the AEC industry. Such imagery is normally pay-per-view or pay-per-download. We’ve taken the bold step of offering unlimited views of your project area, from any of our suppliers, for a single and simple subscription. Download your free trial today to get full access to premium imagery, without even a watermark.

Lambros Kaliakatsos is a civil engineer, engineering software developer, and CEO of Plexscape. He holds two degrees and is a published co-writer in four scientific journals. A decade of AEC experience taught him that missing or low-quality data, especially in the early stages of designing, can lead to significant delays, revisions, and costly rework. His vision became, and still is, for designers worldwide to have easy access to the best, up-to-date aerial and satellite data. This will make for quicker, better, and more informed decisions, thus building a better world for everyone. Plex-Earth, the software he first created in 2009 to join AutoCAD with Google Earth, has already changed how thousands of engineers work. Today, via big improvements and direct partnerships, it gives affordable access to major imagery providers such as Airbus, Maxar, Nearmap, and Hexagon.

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