Digital Film: A New Era of Sensors for Surveying and Mapping
We are entering a new era for sensors that will reshape the quality of data that geomatics and surveying professionals have to work with—for the better. More significantly, the advancements in sensors will alter the way that collection companies work with their clients, and that new relationship will enable each tier of the geospatial industry to pursue higher-level, higher-margin work than in the past.
The Long Reign of Film
It’s probably a safe bet to guess that all of you have been on a plane, but I doubt that many of you have been in the belly of a plane. In fact, I would venture to guess that none of you have spent more time than I have in the belly of planes (or the underbellies of helicopters, for that matter). More specifically, I am talking about the bellies and underbellies of aircraft equipped with high-resolution cameras and geospatial sensors that collect the data that is the lifeblood of our industry. Those areas are often cramped and hot and full of places to bang your head or elbows on things made of metal. But it’s where everything starts for our industry: cameras and sensors strapped to the bottom of tons of metal hurtling through the sky over cities and towns and agricultural fields and natural areas and everything else that people want to see from above. So how have sensors changed since I first started squeezing into tight spaces in the bellies of aircraft?
To be perfectly honest, geospatial sensors have changed relatively little since I started my career years ago. If I could have hopped in a time machine back at the
|A Goddard Rocket Camera being used in the past; the same film technology is still in wide use today. Guevara says “digital film” will finally retire this film-based technology.|
beginning of my career and zoomed ahead to today, I wouldn’t recognize iPhones and the latest Self-Parallel Park, Self- Drive and Collision Avoidance Car models, but I would feel perfectly at home in the bellies of most aircraft that capture geospatial data. That is because in many fundamental ways, those cameras are largely the same as they were 20 or 30 years ago (or event decades ago when adventurous pioneers in our industry first started strapping cameras to balloons, miniature rockets and anything else that could get off the ground up to where the birds roam free).
Many of the geospatial cameras that capture imagery for your day-to-day work still use film just like in the old days. There’s a good reason for that: the advancements that have been made with sensors over the past decade or two are great for some applications, but they have a number of downsides for precision geomatics and mapping. Digital sensors have a lot of positives, but for the most part it has not been a fit for your work. In the debate between digital and film, the only sensible choice for precision mapping has typically been to go with traditional technology. These same film cameras have long been the dominant technology for the geomatics work that POB readers focus on. Film has long been the king of the hill, but that is about to change because sensors are entering a new era that offers the best of both worlds. I call it the “digital film” era.
The Era of “Digital Film”
Film has had a long life in this industry for good reason. It’s not inertia and resistance to change. It’s simply that film has advantages that make it ideal for surveying and mapping. One of its strongest attributes is its ability to achieve 0.6 base-to-height (b/h) ratio for engineering-quality precision mapping. Base to height ratio is the distance on the ground between the centers of overlapping photos, divided by aircraft altitude. In traditional photogrammetric registration using aerial photos, b/h ratio between 0.35 and 0.75 is needed for manual photo interpretation and an overlap ration range from 55% to 60% is recommended for good results—particularly for projects that require stereo imagery. Film cameras, by the nature of their film format, meet those requirements perfectly. In the past, digital cameras did not.
Even more importantly, traditional film cameras freed users from having to worry about technical specifications like b/h ratio at all (although in comparison to digital sensors, a more laborious and expensive end-to-end workflow). Those cameras made those specifications invisible by delivering exactly what the job required without forcing people to waste brain power thinking about those complex technical issues. In that way, the technology was transparent: It did its job without forcing collection companies or imagery users to think about the technology.
|An image taken with the Goddard Rocket Camera.|
In contrast, traditional digital cameras forced people to think hard about the technology and fuss over the b/h ratio and other technical issues that are important for the kind of metric mapping and geospatial projects professionals work on every day. That made digital cameras the opposite of transparent. They were in your face, distracting you from the real work you wanted to focus on. All of that will soon be history, though, because the new generation of digital sensors are eliminating the either/or choice about film vs. digital.
Some of the newest digital sensors on the market have eliminated this divide between film and digital by delivering a b/h ratio and other technical specifications that align perfectly with what mapping and surveying companies have relied on for so long with imagery from film cameras. These sensors can generate one foot contours (30 cms) with engineering metric confidence and their true color technology (non-pan sharpening) provides color radiometric fidelity not achievable by monochrome pixels that get painted by RGB cones. They also produce the geometric accuracy that users need in exactly the format they require. The digital cameras can also be linked together to produce very, very large frames without any impact on resolution and geometric accuracy, just like film cameras.
Even more importantly, these sensors deliver that without forcing collection companies and imagery users to think about the technology. It is transparent just like film cameras have always been. It churns out the imagery that is required, and everyone gets to focus on the job at hand rather than on the sensors. This eliminates the barriers that have long stood in the way of replacing the hundreds of film-based cameras that are still in use by geoimaging companies around the world. That isn’t the end of the story, though. The impact is a lot bigger than just replacing old film cameras.
Digital Film and the Reinvention of the Geospatial Industry
The bigger impact of this transition to digital film will be on the structure of the industry and the evolution of the business models of each tier of the geospatial industry. Let’s start with collection companies: Geoimaging companies who currently still rely on film cameras are limited by that technology and focus largely on selling the imagery rather than providing value-added services to their clients. Film has long been an obstacle to moving into those higher-value services, but digital film changes all of that because the digital nature of the imagery allows collection companies to do more processing of the raw imagery to meet the needs of their clients. Digital film sensors will also allow geoimaging companies to meet the broadening imagery needs of clients, including oblique and true 3D. The bottom line is that this new generation of sensors will enable these collection companies to move up the food chain with sensors that can do much more at a lower cost, while also delivering value-added imagery and data that makes them a key part of their client’s supply chain.
This evolved business model for collection companies meshes perfectly with the way business models for other geospatial companies are evolving. The handful of very large companies at the top of the geospatial industry are redefining their business models to pursue more advanced projects that require their unique resources and expertise, and in the coming months and years we will see them deferring more and more of the mid-market to the middle tier of geospatial companies. That will create tremendous opportunities for growth for the tier of geospatial companies below the “big boys”, and that tier of companies will want to focus on the most profitable aspects of these new projects rather than spending so much time processing raw imagery. This means they will rely more and more on their vendors (i.e. the collection companies) to take on more responsibility. Raw imagery will no longer be enough. They will want value-added services, and the new generation of sensors and related software that collection companies now have at their disposal is the lynchpin for all of that.
Digital Film is the key to this evolution of the industry because it transforms these aerial cameras from just collectors of raw imagery to information-producing tools that drive the entire chain of workflow all the way up the rest of the geospatial food chain. Collection companies will no longer simply take the pictures, develop the images on analog prints and then send the scans to clients. Now they will be true information companies that play a critical role in creating a foundation for what the geospatial industry will be for decades to come.