Focus on new technologies
Law enforcement and security organisations need to be constantly investing in new technologies to keep pace with the latest surveillance and visual image products available. In this article, Adam Smith looks at advances in multi-angle oblique imagery.
Australian government agencies were supplied last year with a new development in aerial imagery to boost security and emergency reponse operations for the 2007 APEC forum in Sydney.
Called Pictometry, it was the first time commercial, oblique imagery had been used as a visual intelligence tool on that scale in Australia.
Pictometry is a technological advancement and already a standard in the USA. It has only recently reached Australian shores. This technology delivers multiple angle, oblique imagery in combination with intuitive measurement tools not seen before in the security and emergency response marketplace.
The ability to develop security plans for events or to respond more effectively in situations requiring a tactical response has been made easier through the adoption of the Pictometry technology. This technology comprises a digital capture component (five digital cameras and an onboard direct, georeferencing unit) in combination with a user interface for data access.
AAMHatch Pty Ltd, a leading geospatial company in Australia, is undertaking a "capture program" over all Australian urban areas using this new, multi-angle, aerial imaging technology. Oblique imagery has been around for a long time, however, the ability to integrate this imagery with geospatial applications and undertake analysis in virtually any urban area, is new.
Geospatial software
Using everyday geospatial software, it is simple to obtain from these powerful oblique images measurements such as location, distance, height, elevation, area and other dimensions of buildings, properties and land features directly from the digitally captured oblique imagery.
So what is the advantage of obliques over traditional images? The most telling feature of what oblique images provide is perspective – and lots of it. Suddenly a flat box representing the roof of a house in a photo mosaic is a seven-storey building at the front and a four-storey building at the back, which you can look at from all directions with a few mouse clicks.
You can see the trees and surrounding features – which ones will obstruct the view from street level and which ones could provide cover. Building entrances for access and egress are clearly visible. Obliques put tactical support staff into the physical environment instantly providing real "situational awareness" but with safety.
Law enforcement, public safety and emergency response personnel find oblique imagery far more intuitive and information rich than traditional seamless photo mosaics.
Other benefits include the speed at which imagery of a given area can be captured, processed and ready for use viz: days not weeks, as well as the ability to integrate the imagery with other third-party geospatial systems like ESRI ArcGIS and the cost savings associated with use of the imagery.
Respond to a bomb threat
Imagine having to respond to a bomb threat in a building utilising pre-event imagery taken from all angles.
The multiple view imagery permits rapid planning for evacuating people and dealing with the crisis. The size of the building is known, entrances are no longer obscured, the material of the building may be visible and the height and width of windows can be determined to calculate glass area. All this from a command post or mobile system deployed with first responders.
The oblique angles of the imagery makes it is easy to demonstrate the "lay of the land" and assess the most effective and least dangerous way to respond to the situation.
Scenario- Building Bomb Threat
Benefits of multi-angle oblique imagery for dealing with a bomb threat.
-determine building has two street access
-determine building is seven stories high at front and four stories at back
-identify the number and location of entry points
-calculate height of windows off the ground
-calculate height of the building on several sides.
There has been a surge in the use of oblique images by police, fire and emergency response teams at the local, state and national levels. This surge has allowed more people who understand public safety, but not technology, to use tools that can help them do their jobs.
For instance, in Gwinnett County, Georgia in 2005, police closed in on a fugitive, a detainee who shot four people in a rampage at a courthouse the day before. Worried that aerial surveillance might alarm the fugitive, who was hiding in an apartment building, the county's SWAT team opted for oblique images of the complex to plan the gunman's capture.
Responders were able to place themselves in the physical environment with aerial perspective of what they couldn't see from the ground. They could optimally place officers, observe details of entries/exits, fencing, windows and the location of garages, trees and other buildings, which could be used for cover.
In the US, Polk County's 911 service became the first in the country to integrate oblique imagery with GIS. When an emergency call comes into the county's communications centre, the caller's location coordinates are displayed with an oblique image as well.
In addition to allowing the fire department to measure objects and buildings, dispatchers can use the images to assign alternate traffic routes to incidents, scope each address from multiple angles for entry and escape routes, and provide guidance on the location of electrical wires and other obstacles that might obstruct rescue equipment or helicopter access.
Night time incidents
Oblique images have been an enormous benefit to responders of night time incidents. Often, first responders will drive by the location because it is hard to identify a building or house in the dark. With oblique images, responders can be advised of details that can not be seen in the dark, or what is on the roof or in the back lane.
Another example is the use of oblique imagery during the devastation of Hurricane Katrina. When responders visited the flooded streets of New Orleans right after the storm, they could not identify buildings or houses. With the oblique images integrated with GIS, commanders and dispatchers could tell personnel on site what structures they were seeing.
Emergency management officials can use before and after incident, oblique photos to detect changes and assess damage, cost of repair, as well as evaluate plans to rebuild versus demolish damaged property.
Other valuable products can be derived from this oblique imaging, including 3D city models which fuel a range of other applications and form the basis of simulations and fly-throughs. Councils in Sydney and Melbourne will soon be recipients of this imagery.
Without a doubt, the growing use of oblique aerial images worldwide is having an impact on emergency management operations. As technologies continue to advance we're likely to find high-resolution, oblique imagery, integrating more and more with geospatial systems to fill capability gaps in our effort to keep the country safe.
About the author: Adam Smith is the business development manager, security and federal government for AAMHatch Pty Ltd. AAMHatch is a leading geospatial information company.