Archive for August, 2021

A local cycling example of GIS as a system of engagement

August 30, 2021 2 comments

For many years I and others have been speaking about two intertwining forces in geotechnologies: (1) That GIS has moved from a system of records to a system of engagement, and (2) the connection of mapping to the citizen science community. On (1), to be sure, GIS still is fundamentally tied to records, and indeed, without the spatial and attribute data, you have no GIS. However, GIS is not primarily simply about recording natural and physical objects on, above, or below the surface. And I salute the many people involved in encoding this volume of information, as I used to do in the past at the USGS, and what thousands of dedicated individuals do on a daily basis today.

But these records are not collected just to populate a database or even just to map things: They are created to serve a higher purpose–to enable organizations to make smarter decisions about what is there and what should be there; to forecast, to model, to plan. In addition, data-as-services and software-as-a-service together with field tools allows the public to be engaged in their community as never before. Coupled with that is (2), the citizen science or community science movement, which is nearly 150 years old, but now is seeing rapid expansion given the community’s newfound ability to map the data that they are collecting. Recently I experienced both of these at a personal level.

My city of Lakewood, Colorado USA, has a great web GIS map of trails, and also a request portal through which community members can report about and request things that are in need of repair or otherwise of concern. My community also has a number of data services through the efforts of its excellent GIS staff, including cycling, walking, and hiking trails. Why not, I thought, put my interest in my community, my interest in GIS, and my interest in cycling to the test and try out this request portal? I went cycling and identified a few places of concern to me and surely to other cyclists. I then went to the citizen portal and identified those areas with the photos I had taken. To my surprise, the parks and recreation people called me and asked for further clarification! I provided it, and as you can see in the photographs below, two days later, the places were marked, and two days after that, they were repaired! I called the parks people back to express my gratitude and also emailed and called the GIS staff as well.

Once again, the power of GIS at work! Call me a “satisfied community member”.

This crack in this trail is not a big deal if you are just walking, but to a cyclist, it is just wide enough and at a steep part of the trail to cause significant jarring of your front tire when you hit it.
The crack has been filled! Hooray.
Due in large part to some pretty active roots, the asphalt along this section of trail is full of bumps and cracks. Again not that big of a deal to a hiker, but a big deal to a cyclist.
Just two days later, I noticed these spots had been marked for repair!
Two days after that, the cracks had been filled (see right side) and the broken parts of the fence had also been repaired!

Categories: Public Domain Data

What is the value of location data?

August 16, 2021 Leave a comment

My colleagues here at Esri wrote what I consider to be an excellent essay on the business value of location data and why it matters. In their essay, (, they make it plain that while this value is more difficult to quantify than, say, a HVAC unit or the revenue of a store, the effort of pinpointing the value is definitely worth doing.

For example, Highways England pegged the value of its physical road infrastructure at £115 billion, a staggering amount, but yet the intangible value it delivered to the country was calculated to be even more, at £200 billion!  The latter figure was not a simple estimate, but arrived at only after nearly a year of extensive data gathering, including interviews with those touched in some way by the work of the highway agencies.

Why does all this matter? The article points out that only 16% of business assets are tangible assets nowadays. The implications of this percentage are clear: Businesses need to be able to understand the value that location data brings, and articulate this value to their stakeholders, customers, and CEOs. In addition to building this shared understanding, purpose, and lexicon, doing so yields additional benefits. For example, through examining the value that data brings to an organization and to the greater society, the business featured in the article put together a case for new investment, as well.

For a related article, see our Spatial Reserves essay on Putting a Value on Geospatial Data and this recent Forbes article. on “how much is your data worth?”

Joseph Kerski

Categories: Public Domain Data Tags:

AirTags: Who’s watching who?

August 9, 2021 3 comments

When I saw the announcement about Apple’s new AirTags, my first thought was to forget tracking the location of my personal possessions, I could use one of these to track my elderly, and occasionally forgetful, Mother. Attach an AirTag to her bag, subject to her consent, and I’d be able to keep an eye on her whereabouts when she heads out to walk her dog.

However, not long after the initial release and reassurances that location privacy was an integral part of the design, a software update for AirTags was made available to counter unintended or surreptitious tracking by other suitably enabled devices in the vicinity. The initial configuration for sending safety alerts for an AirTag separated from its paired iPhone or the presence of AirTag not owned by you but in some way tied to your location (nearby or slipped into a pocket?) and tracked by others, meant alerts were not triggered for three days if you didn’t have an iPhone with IOS 14.5 or had an Android phone. Given the number of iPhones in circulation and the extent of Apple’s Find My network, millions of people could be tracked unwittingly through AirTags and be none the wiser for three days. Even after an upgrade to iOS 14.5 and the AirTags software update, it could still take a couple of hours to alert an iPhone owner to the presence of a so-called stalker AirTag. Chances are nothing would happen but is broadcasting your location like this worth the risk?

In this day and age of heightened awareness of creepy apps, issues related to location tracking and so on, it seems odd this particular scenario hadn’t been considered as a potential security threat. As Brenda Stoylar noted in her Mashable article …

AirTags are easy to use and effective, but their extensive location tracking and ability to go beyond Bluetooth range is also what makes them dangerous for the rest of us.

What makes AirTags potentially dangerous to use is the lack of detailed information describing how they work and a lack of transparency in how location information is, or could be, collected.

50-60 year old Spy Imagery as a source of historic data

August 2, 2021 Leave a comment

Throughout the 1960s and 1970s a top-secret US program dubbed Corona by the Central Intelligence Agency (CIA) captured 800,000 images via satellite of many places around the planet. As an interesting piece of GIS and remote sensing history, the film canisters from these satellites was periodically jettisoned, and physically retrieved in midair via aircraft. The logistics involved in such operations are amazing for their time, and even now. The imagery was declassified in 1995. At that time, I was working as a cartographer for the USGS, and we started offering prints of the Corona imagery then. I remember poring over these prints at our large mapping facility in Denver, considering the vast amount of change evident in a relatively short (30 years) time since they had been collected.

New developments in GIS technology are breathing new life into this set of imagery, making it increasingly available and applied to a wider variety of uses. For example, my colleague Mariah Petrovic wrote a fascinating article about how this imagery is being used to address climate change, here. These include past habitats, water scarcity, and shoreline change. In addition, the imagery is being used to identify archaeological sites and much more.

Now some of this imagery is available in digital form as part of the growing array of truly Big Data sets. One way to access is via the USGS Earth Explorer portal. Another is via the Corona Atlas and Referencing System at the University of Arkansas. Some of the data accessible via the university’s data portal is from satellites that were equipped with two panoramic cameras, one facing forward and another aft, with a 30º angle of separation, producing an approximate ground resolution of 6 feet (1.8m) at nadir. They also offer the capability for stereo viewing, and the extraction of topographic data. Images were originally recorded on black-and-white film. The USGS scanned the images at 7 micron (3600 dpi) resolution. Additional technical details regarding the CORONA program and image characteristics can be read here.

Begin by exploring the data, available here. The atlas allows you to measure, identify, search, swipe, and perform other visualizations on the data. Map layers can be toggled using the Map Contents menu. Some map layers are expandable, allowing sub-layers to be turned on or off. Use the plus sign (+) next to a layer to access sub-layers. Use the blue down-arrow next to an image to download the source data, as shown below:

Downloading the Corona imagery.

The data formats include: (1) GeoTIFF – orthorectified and reprojected to use the “Web Mercator” projection. These should be ready for use in any GIS package that can read GeoTIFFs. The NITF version of this image will require the user to obtain appropriate elevation data to be used in the orthorectification process necessary to display the image in the correct position on the earth’s surface. More information about this process can be found here. This image has not been resampled as has the GeoTIFF listed above, so it is closer to the original imagery. The website helpfully provides coordinates that can be manually input as the data selection coordinates to download SRTM elevation data from; for example, for the image above: X-min: 32.428226 Y-min: 35.190579 X-max: 35.394672 Y-max: 35.827378.

Corona imagery for a section of Missouri USA.
Corona imagery for the Great Pyramids at Giza, Egypt.

I encourage you to investigate this amazing resource.

Joseph Kerski

Categories: Public Domain Data