Earlier this year we wrote about the launch of the European Space Agency’s (ESA) Sentinel-2A satellite and the mission to deliver a range of data products including land cover maps and bio-geophysical data. ESA have just released the Sentinel-2A orthorectified products, which are now available to download for free from the Sentinel-2 Data Hub https://scihub.copernicus.eu/s2/.
ESA have also posted a data quality report to document the current status of the data and provide information on product formats and features. As the programme is currently in a ramp-up phase, further improvements in the extent of coverage and the accuracy of the products are expected over the next few months.
Earlier this year Michael F. Goodchild, Emeritus Professor of Geography at the University of California at Santa Barbara, shared some thoughts about current and future GIS-related developments in an article for ArcWatch. It was interesting to note the importance attached to the issues of privacy and the volume of personal information that is now routinely captured through our browsing habits and online activities.
Prof. Goodchild sees the privacy issue as essentially one of control; what control do we as individuals have over the data that are captured about us and how that data are used. For some the solution may be to create their own personal data stores and retreat from public forums on the Internet. For others, an increasing appreciation of the value of personal information to governments and corporations, may offer a way to reclaim some control over their data. The data could be sold or traded for access to services, a trend we also commented on in a previous post.
Turning next to big data, the associated issues were characterised as the three Vs:
- Volume—Capture, management and analysis of unprecedented volumes of data
- Variety—Multiple data sources to locate, access, search and retrieve data from
- Velocity—Real-time or near real-time monitoring and data collection
Together the three Vs bring a new set of challenges for data analysts and new tools and techniques will be required to process and analyse the data. These tools will be required to not only better illustrate the patterns of current behaviour but to predict more accurately future events, such as extreme weather and the outbreak and the spread of infectious diseases, and socio-economic trends. In a recent post on GIS Lounge Zachary Romano described one such initiative from Orbital Insights, a ‘geospatial big data’ company based in California. The company is developing deep learning processes that will recognise patterns of human behaviour in satellite imagery and cited the examples of the number of cars in a car park as an indicator of retail sales or the presence of shadows as an indicator of construction activity. As the author noted, ‘Applications of this analytical tool are theoretically endless‘.
Will these new tools use satellite imagery to track changes at the level of individual properties? Assuming potentially yes, the issue of control over personal data comes to the fore again, only this time most of us won’t know what satellites are watching us, which organisations or governments control those satellites and who is doing what with our data.
The European Space Agency (ESA) recently launched their latest environmental monitoring satellite, Sentinel-2A, adding high-resolution optical imaging capability to the radar imagery provided by the first satellite in the Copernicus fleet, Sentinel-1A. Tasked with combining wide swaths and short revisit times (5-day cycle), Sentinel-2A will monitor land and vegetation change to deliver a range of data products including land cover maps and indices for a number bio-geophysical variables. Although the commissioning phase will last for about three months, Sentinel-2A has already recorded its first images.
Once operational, Sentinel-2A’s imagery will be hosted on the Sentinels Scientific Data Hub, which will be upgraded shortly to accommodate the new satellite. The data will be available on a ‘free and open’ basis to any users registered with the data hub. Although the data will be made publicly available, they will not be in the public domain and remain the intellectual property of Copernicus Programme. However, subject to the ESA’s terms and conditions, users are free to user, alter, modify, publish and distribute the data. Judging by the first data samples, Sentinel-2A’s imagery will provide an invaluable resource for global environmental monitoring.
The first imagery from DigitalGlobe’s WorldView-3 satellite, launched in early August 2014, has already been received and although still in the testing and calibration phase, the imagery has been lauded a new standard in resolution (maximum 31 cm) and clarity. Despite the fact that the imagery was taken from an altitude of approximately 620 km, the images provide a level of detail and image sharpness that were previously only available from aerial photography.
Samples of the data are available on the DigitalGlobe and Mapbox.com sites and include imagery from Barcelona and Madrid in Spain. From the airport imagery it’s possible to identify individual planes, runway markings and other detailed airport infrastructure.
In addition to the improved resolution, WorldView-3 incorporates additional spectral bands (29 in total) to sense previously undetected changes in vegetation, variations in surface composition, moisture levels and building materials.
We’ve previously written about the launch and progress of the Sentinal-1A satellite, part of the European Union’s Copernicus earth observation project. Although still being commissioned and not yet in full production mode, the satellite recently provided radar imagery from Northern California captured before and after the Napa Valley earthquake on 24 August.
Using a technique known as ‘Synthetic aperture radar interferometry’, two images of the same area were compared to identify areas of significant change. Changes to the ground surface modify the reflected radar signal detected by the satellite, and those modified signals can be plotted as an ‘interferogram’ (Source: Radar vision maps Napa Valley earthquake.) The result is both colourful and striking; the fault responsible for the 6.0 earthquake was confirmed as the West Napa Fault, and both the scale and the extent of the surface rupture was immediately apparent.
Imagery like these examples captured for the Napa Valley quake looks set to transform how scientists and data analysts map and respond to earthquakes. With the launch of second Sentinel satellite (1B) in 2016, the imagery update cycle will be reduced from 12 to 6 days. The timely and open publication of high resolution data to support activities on the ground and post quake analysis after each event, should provide unprecedented monitoring of the Earth’s surface.
In April we wrote about the launch of the Sentinel-1A satellite, part of the European Union’s Copernicus Earth Observation project, and the plans to make the data publicly available. Although the satellite is still being calibrated and not yet fully operational, it has already provided some radar data to help support the recent flood mapping activity in the Balkans. As the radar on-board Sentinal-1A can operate through cloud, rain and in darkness it is especially useful for monitoring floods.
After persistent heavy rainfall resulted in widespread flooding and a number of landslides in Bosnia and Herzegovina, the emergency services needed access to accurate and current maps of the region to support the relief effort. The data from Sentinel-1A helped identify areas of flooding that the emergency services were unaware of.
The Sentinel-1A satellite has also helped monitor flooding when the Zambezi River burst its banks in April, inundating the border between Namibia, Zambia and Botswana. Data from the satellite were made available to the Namibian authorities within three hours of collection, providing near real-time information for an area had been difficult to survey on the ground.
Given the impact Sentinel-1A has already had, the Earth Observation project looks set to make a major contribution to environmental monitoring and assessment. The satellite will soon be fully operational, helping to provide some of the data that will support a more holistic approach to environmental management.
Last week the European Union (EU) announced the launch of the Sentinel-1A satellite, as part of the first of six missions that will provide the framework for the Copernicus Earth Observation project. Copernicus, formerly known as GMES (Global Monitoring for Environment and Security), aims to collect data from a variety of sources, including satellite, airborne sensors and ground stations, to support a range of applications including:
Monitoring sea ice zones and the Arctic environment
Assimilation of sea ice observations in the forecasting systems
Surveillance of marine environment, including oil-spill monitoring and ship detection for maritime security
Monitoring land surface motion risks
Mapping of land surfaces: forest, water and soil, sustainable agriculture
Mapping in support of humanitarian aid in crisis situations
A second satellite, Sentinel-1B, will be launched next year. Once the system is fully operational, the aim is to provide almost daily coverage for high priority areas like Europe, Canada and some shipping routes. The radar capabilities on-board the satellite mean that data can be collected independent of weather conditions, day or night.
Image source: http://bit.ly/1el9g6M
All of the data products collected by the Sentinel satellites are to be made publicly available as open data, free of charge, to all data users. This also includes the use of the data for commercial purposes. The Sentinel-1A satellite is expected to be operational within three months.