If you see a twin-engine airplane this week flying low over your house or office taking pictures, don’t worry.

It’s not voyeurs or spies or the police. It’s the mapmakers.

The city of Los Angeles is paying an Orange County firm $1 million to take very, very detailed photos of every inch of L.A. The 2,300 black-and-white pictures of the city’s 550 square miles will give businesses and the city the best images they’ve ever had of one of the largest urban areas in the world.

The photos, once they are digitized into a seamless computer map, will be so detailed that viewers will be able to make out light posts and manhole covers.

“We come out with images that are basically maps or smart photos,” said Joseph Bartorelli, general manager for Hammon, Jensen & Wallen in Irvine, which has the contract to take what are called “digital orthophotographic images.”

Using a $600,000 camera, HJW will send a pilot and a crew up late this week to start snapping pictures from 3,600 feet in the air. When the photos are rendered into computerized maps, each pixel on the map will equal 6 inches on the ground.

The mapping company is doing the project for the city’s Department of Public Works survey division. But the results will be shared with other departments, including Planning, Building and Safety, Transportation, Police and Fire.

“It is something that has been done in a number of other cities,” said Kurt Reimers, survey party chief for the Department of Public Works. “We are one of the latest ones in the area getting into this because of the size of the city. It takes so long to get moving toward this stuff.”

Other cities that have mapped their streets and hills using digital orthographic images include San Diego, San Francisco, Oakland, Santa Monica, Torrance and Riverside.

In Riverside, the city has been using the technology for two years. “We use it for everything,” said Brad Mayo, project manager for Riverside’s Geographic Information Systems. “You know the phrase, ‘A picture is worth a thousand words.’ Well, that’s true here. A lot of people look at a map and don’t understand what they are looking at when they see all those lines. If you put a digital orthophotographic image over those lines, it shows an additional level of context.”

Web photos

Riverside already has a detailed graphic map outlining every local street posted on the city’s Web site. But eventually, digital photographs will be added to the Web graphic maps, giving a better idea of what’s out there.

Digital maps help commercial real estate brokers and residential agents get an overall view of a property they want to develop or sell. The maps can show in greater detail than ordinary maps what amenities exist in the area, such as parking lots, shopping centers, schools, parks and highways.

In Los Angeles, the photographic images will help city officials do a better job of planning and delivering services, using a single map laid out from just one source. In the past, the city has relied on topographic maps that have been added to piece by piece, sometimes using different technology or methods.

The Bureau of Engineering will be able to use the digital maps for new projects. If engineers want to put in new storm drains, streets, sewers, or public works projects, they can pull up a detailed map and see what is already out there without having to drive to the area.

“We’ll be able to see where the trees are and where the vacant lots are located,” Reimers said. “We can see what undeveloped hillsides might have old dirt roads that aren’t used anymore.”

When doing street repairs and improvements, city officials can pull up a detailed map and look at how the road is configured to determine how they want traffic to be re-routed during construction.

The Los Angeles Fire Department already has aerial photographs to help officials determine how to fight fires. But it eventually will be getting the digital maps because they are 6.5 times more precise than what they have now, said Janos Szaktilla, the department’s acting supervisor of maps and drafting.

“The Fire Department can use these detailed maps for several things. One is to see vacant areas where there are no buildings. If there is a fire, we can plan how to attack it. It also shows us the type of vegetation that is on the land and what kind of fuel content the plants have. If there was a recent fire, the fuel content of the vegetation is low,” Szaktilla said. “Another benefit for the Fire Department is that with these photos, we can see which properties have swimming pools, which is an important source of water.”

Police, fire uses

A third benefit is that the maps will make it easier to fight fires at large industrial buildings. If a fire breaks out in one of the structures, fire officials can pull up a picture of the building and determine from which side to enter it.

The Los Angeles Police Department will also have access to the new aerial maps.

“There are a tremendous number of things you can do with these maps,” said police Lt. Joe Hiltner, in charge of the department’s deployment and design section. “You could detail a crime scene or diagram whatever you need at the time.”

The maps would help police officers see where alleys, fences and dead-end streets are located, to help them in their pursuit of suspects.

While these maps will help give a better picture of the world we live in, they will be good for only so long. Like all cities, Los Angeles is changing, which means the maps will have to be updated again in five years or so.