Bringing New Meaning to Photo Imaging

By Scott S. Weinberg, FASLA

As a landscape architect, when was the last time you made an initial site visit only to discover you missed some important site features essential for a correct base map or site analysis. Perhaps this meant only a quick drive to the site or in a severe case, a long journey by plane to obtain the needed information.

Today, those "back up" site visits may not be needed. Of course as designers it is necessary to make that initial site visit. No product can take the place of seeing, feeling, touching and smelling a potential project site. However, with the technology developed by Pictometry, long note taking site visits may be a thing of the past.

This photo shows a cropped version of suburban Atlanta taken at the "community" altitude of 5,000 feet.

I can remember sitting in a photogrammetry class in college, looking at pairs of aerial photographs through stereoscopes and trying to identify what was really happening on the ground plane. Was it a building or a large dumpster? In most cases it was purely an educated guess. The people at Pictometry have removed the guesswork from "old fashioned" aerial photographs and have replaced the old method with a new and very powerful way of conveying site information through photos. The methods are so unique, they have been patented.

The way the company obtains the data is to create aerial photographs taken in two stages. Stage one is a flight that at 5,000 feet. This produces photos that are about one mile square. In stage two, photos are taken at 2,000 feet and produces photo images that are 750 feet square. Each 5,000-foot photo is broken down into 49 individual 750-foot photos. These photos are taken at 90 degree and 40 degree angles. The paths are set up so that a series of pictures are taken from north to south, south to north, east to west and west to east. This allows for every parcel to be documented on all sides. When completed, each object or site can be seen from as many as 12 different views. You won't miss the windows on the south side of the building with these photos.

This is an example of how you can measure height and distance from a photo. It also provides location information.

It is important that these photos be taken when there is no leaf cover, to have the all of the ground plane information clearly available for photography. In most cases these photos are updated every two years. Depending on the size of the area being photographed it may take from two days to two weeks to completely document the ground plane.

The Pictometry system will allow the user to gain a clearer visual perspective of the site. It also allows use of a number of "tools" to enhance the information that the images contain. Here is a partial listing of some of the tools and what they can do using the system:

• Distance Tool: Measure the length, width or perimeter of any feature.
• Height Tool: Measure the height of buildings, trees, light poles or anything that has a third dimension.
• Location Tool: Obtain, gather and export geo-coordinates of any ground feature.
• Area Tool: Measure the acreage or square footage of any area on the image.
• Elevation Tool: With a simple click of the mouse, ground elevations are made available.
• Bearing Tool: Determine the precise orientation from true north.

Using any of the above tools is a easy. With the two resolutions of the photo images, it is possible to be very accurate when taking measurements. The 5,000-foot photos offer a resolution of two feet per pixel. In most cases you can be within two feet of an exact on-the-ground measurement. Using the 2,000-foot images, the resolution is focused down to six inches per pixel, which is about what you would expect from an actual site visit.

The Pictometry system is available as both a stand-alone product or on the web for specific sites. The stand alone can be used for a city or county site where the entire area is flown and updated on a two year cycle. For this there is no seat limit. Anyone in the organization has the ability to access the information. Using the site specific, web-based system there is an annual charge, a charge for "maintenance," and a per seat charge. Looking at their present pricing structure, any firm large or small would benefit from this system by not having to fly to a site and incur the expenses related to a trip.

The resolution of the films provide great detail. Notice you can easily see street lights and mailboxes.

In their ads and on their web page, Pictometry claims that they can do their training and have you up and running in about 20 minutes. I would not disagree with this claim. The power is in the seamless integration of the photos and the software. For anyone who needs up to date and accurate site information, this technology would be something to be considered.

You can visit their website for additional information at: www.pictometry.com

Scott Weinberg is LASN's editor of digital information and a professor of landscape architecture at the University of Georgia in Athens. Weinberg is also the dean of UGA's College of Environmental Design./p>