More Than Aerial Photography

Law & Order, September 2005 | Go to article overview
Save to active project

More Than Aerial Photography


When planning a tactical operation, maps are good, aerial photos are better, and having both is great, although it doesn't happen very often. When aerial photos are available, they are usually outdated, taken from directly overhead of the objective, and are not detailed enough to show man-on-the-ground features. What if you could have aerial photos that were tied to a computerized mapping program, not more than two years old, showed detail as small as six inches, and offered views from all four compass points?

The image sets offered by Pictometry® do just that. Using proprietary methods and technologies, Pictometry produces extremely detailed sets of aerial images of an entire county, with every feature and landmark photographed from multiple angles and resolutions.

The images are all digital, and are linked to a computer-based map of the entire surveyed area. By clicking a mouse on the area of the map to be viewed, the user is taken to a screen showing all available views of that area, and can then select the ones best suited for the task. Users can zoom in on any image to pick up additional detail.

Orthogonal and Oblique

The images from any one county make up one complete set. When they are contracted to produce the image set, a Cessna 172 light aircraft overflies the county in strips, collecting digital photos with specially designed cameras. Overflights are made at approximately 5,000 and 2,500 feet, and from all four compass directions.

The images are also from two views. The orthogonal view (straight down) is like a map or traditional aerial image, and is useful for planning and orienting against a standard map. Oblique (angled) views are from a perspective of about 45 degrees, and show detail of the sides of buildings, signs, and other visual information that might not be so obvious when seen from directly overhead.

The value of these oblique views should not be underestimated. Even though very tall buildings are obvious when viewed from the conventional ground-level perspective, there is no sense of their height when viewed from directly overhead. It is virtually impossible to distinguish a 20-story building from a one-story building with a similar perimeter, unless there are shadows or other cues that give it away. With the oblique view, the difference between structures becomes instantly evident.

The resolution of the images is extremely high. Images taken from the higher altitude, called community views, resolve to about two feet per pixel, where the neighborhood view images from the 2,500 foot altitude are at about six inches per pixel. This is plenty sufficient to see the placement of doors, windows, clotheslines, doghouses, and other details that would be useful in tactical planning, but not be a threat to personal privacy.

License plates, faces, and other similarly small details are not discernable even at the greatest resolutions and magnifications. Neighborhood images are about 0.5 mile long by 0.25 mile wide, where community view images are about 1.25 miles long and 0.75 miles wide.

In order to reduce costs, rural areas, where there is less need for detail, are imaged at the higher altitude, whereas urban, built-up areas will have the full range of images available. The end result is that every square foot of the county will have at least three and as many as 20 different views available to all users, with an average around 12.

User Interface

The user interface to the Pictometry software is fairly intuitive. On an overview map of the entire county (and surrounding counties, where those images are available) shown in the main workspace window, a blue outline placed by the user identifies the area of interest. A pane to the right of the main workspace has thumbnail views of all the images available for the area identified. Clicking on one of the thumbnails brings it into the main workspace.

For each image, a compass-rose alongside the thumbnail shows the view angle, so that the user does not become disoriented.

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
Loading One moment ...
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited article

More Than Aerial Photography
Settings

Settings

Typeface
Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

While we understand printed pages are helpful to our users, this limitation is necessary to help protect our publishers' copyrighted material and prevent its unlawful distribution. We are sorry for any inconvenience.
Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.

Are you sure you want to delete this highlight?