Geospatial data sits at the heart of solving problems. Problems that affect us globally and problems that affect us locally. At the heart of solutions to these problems is information. Without good information, good solutions will be much harder to find.
Geospatial data is a key technology enabler that can be used to provide information about the environment around us, or used in conjunction with other key technology enablers such as AI, 5G and cloud computing to provide powerful end to end solutions.
Increases in both the currency and the resolution of data are making geospatial data more useful than ever before. We are experiencing a rapid growth in demand for ultra-high resolution 3cm and 5cm imagery for towns and cities, in addition to more frequent updates, but at an affordable price.
3cm aerial oblique image, Southwark, 2020
Getmapping’s purpose is to help people leverage the power of geospatial data and solutions to help organisations overcome their challenges and maximise the potential of their opportunities.
With the upcoming UK flying season commencing at the start of April, David Philpot, Getmapping’s Content Programs Project Manager, provides an insight into some of the challenges Getmapping face in creating national content programs, and how technology is helping us to overcome these challenges and create ever more accurate and detailed data that power solutions for our customers.
Technology is Key
The key to delivering a successful content program lies in utilising the latest capture and processing technology and making the right choices for hardware and software. For example, recent trends in survey camera technology have seen improved CCD sensors that increase the size of the footprint on the ground for each image, meaning that less flying is needed to cover the same area on the ground, or an increased resolution of data can be achieved from the same flying height.
3cm aerial image, Ipswich, 2020
Getmapping has just invested in the latest ‘best-of-breed’ large format camera – the Vexcel Eagle MKIII - which can capture 450mpix per exposure in RGB and Near Infra-Red.
One thing that does seem to be constant, especially in the UK and Ireland, is the unpredictable nature of the weather. So, with large scale capture programmes, using the latest technology ensures that we maximise the capture opportunities that the weather allows.
Choice of aircraft is also critical, and what would suit for large scale capture (longer range, fast transit speeds) may not be suitable for a high-resolution project over a city, where a high overlap between individual images may be a more important factor in achieving the desired outcome for the project and would need an aircraft that can fly slow and low.
However, camera technology is now beginning to overcome this by enabling much shorter intervals between exposures. This enables ultra Hi-resolution capture (i.e.at 3cm resolution or better) that is increasingly requested, particularly for our towns and cities. This affords a view of features on the ground in unparalleled detail, and opens up the opportunity for creating detailed 3D models.
3cm aerial oblique image, Cambridge, 2021
Airspace is a Challenge
In Western Europe, Airspace is becoming ever more crowded, particularly over the larger cities such as London, which of course also have the largest market demand for capture updates. The camera systems we use are chosen to support capture at the desired resolution from an altitude above (or below) these airspace restrictions. One positive effect of the covid pandemic has been that airspace in some areas has been easier to access due to reduced volumes of air traffic, but we expect to see the skies becoming busier again in 2022 as the world begins to open back up for travel. Airspaces above cities like London remain complex and care must be taken in the choice of camera and aircraft to allow the best chance of success in a project.
Large parts of the UK are in controlled airspace, meaning permissions to fly must be applied for and then approved by the air traffic authorities in advance. Permission on the day of survey will depend on the volume of traffic that the controller for that piece of airspace must manage. Most air traffic will only be passing through a piece of airspace for a short period of time, whereas a survey aircraft could stay there for several hours.
Getmapping has 23 years of experience capturing Aerial Photography in the UK and abroad and currently holds contracts for updating the whole of the UK (for the APGB contract) and the Republic of Ireland (for DAFM). Our twenty plus years of accumulated knowledge and experience of operating in this airspace has underpinned our success in delivering these contracts.
High Resolution Doesn’t Automatically mean High Accuracy
For many of our customers, data accuracy is just as important as resolution. A survey aircraft is a dynamic environment, so the camera sits on a gyrostabilized mount to compensate for the movement of the aircraft and is operated in tandem with the latest GPS equipment to deliver high levels of positional accuracy. The aircraft’s GPS data is triangulated with GPS base stations to increase positional accuracy, and the motion of the aircraft (Roll, Yaw, Pitch) is monitored using an IMU (Inertial Measurement Unit) which measures the precise direction the camera is facing for each exposure. This is essential to the process of triangulating and then merging all the images from the flight into an accurate seamless dataset.
Getmapping also collects ground control points to help ensure the absolute accuracy of our imagery. These are known locations on the aerial photography that are measured on the ground with professional survey equipment, to give a 1-2cm accuracy to specific points in the dataset. This further increases the accuracy of the overall dataset.
Using the latest camera technology, with short times between individual exposures, also allows data to be captured with a very high overlap between images - typically each image overlaps the next on a flightline by 80%. This Increased overlap, ever-increasing computer processing power to deal with the large volumes of data captured, together with precise Aerial Triangulation results, allow highly accurate 3D data to be directly derived from the Aerial Photography, as the processing software can assign a 3D coordinate to every pixel in a dataset.
3D Mesh, Southwark, from 2020 data
These principles apply to all the datasets captured, whether they are ultra-high resolution 3cm and 5cm imagery for towns and cities or our national capture programmes for APGB and DAFM. All of the data is flown at an overlap that will allow DSM Orthos to be created and height data directly derived. If required, the sidelap can be increased further to allow for the creation of 3d Mesh datasets for realistic 3D visualisation.
Delivering Powerful Solutions
The increased accuracy, resolution and currency of aerial imagery and geospatial data, particularly when harnessed with the power of other key technology enablers such as AI, are creating a range of innovative new geospatial solutions. These enterprise grade, end-to-end solutions are being created for both GIS and non-GIS experts alike, who are increasingly looking to geospatial data for solutions to the challenges and opportunities they face.
For more information on our Geospatial content programmes or to discuss how our powerful solutions could help your organisation, please email email@example.com
David Philpot, Content Programs Project Manager, Getmapping
David has worked at GeoSense and Getmapping for 17 years. He is an experienced Prince 2 certified Project Manager with a wealth of knowledge of all aspects af aerial photography acquisition, image processing and production. His focus is on delivering high quality data to our customers.