Number crunching by the University of Pittsburgh and Pittsburgh Public Schools has yielded two results: a portrait of the children who attend city schools and the most accurate street listing for the city ever.

Both are being released today, the portrait as part of the Pittsburgh Public Schools Data and Technology Atlas and the city street list to city and county officials who will be better equipped to find addresses in emergencies.

The atlas, which is located on the Web at visc.sis.pitt.edu, compares January 2004 numbers with this past January's to show trends and patterns in the city schools.

City school enrollment overall fell 3.8 percent from January last year to January this year, from 33,796 to 32,505. Currently, 56.6 percent of the students are black, compared with 56.2 percent last year.

Christopher Temple, senior geographic information systems analyst for the city schools, said it's common knowledge city school enrollment has been declining for years, but that drop hasn't been uniform.

For example, Perry North has 610 students, an increase of 26.6 percent over last year, but Northview Heights has 462 students, a decrease of 21.6 percent.

Temple and Matthew Kelley, project supervisor for the Visual Information Systems Center at Pitt, also noted other patterns:

The biggest percentage loss is at the middle school level. This year, there are 11.8 percent fewer students in sixth grade than there were last year.

The district has added middle school grades to some elementary schools, and the figures show that the number of sixth-graders in those buildings has climbed 39.2 percent, to 380 students.

The decline, therefore, was felt in middle school buildings serving grades six, seven and eight, but most sixth-graders -- 2,022 of them -- are enrolled in those schools.

There was little change in first-grade enrollment from 2004 to 2005, just two fewer students. However, the drop accelerated in grade two, where there are 152 or 6.2 percent fewer students than last year, and grade three, where there are 197 or 7.8 percent fewer students.

There was the same number of girls in elementary schools this year as last, but the number of boys dropped 2.8 percent.

A greater portion of students districtwide are poor enough to receive a free lunch. Some of the greatest concentrations of those qualifying for free- and reduced-price lunches are in the Beltzhoover-Knoxville area, Homewood, Garfield, Northview Heights and East Hills.

The atlas, which was first released last year, was developed by the Visual Information Systems Center at Pitt and the city school district as part of Project VIPER -- Visualizing Information for Pittsburgh Public Schools Education and Research.

The first version of the atlas was introduced last year. The city school district so far has agreed to fund the work through the end of this month.

In working with the city school data, the researchers plotted the residence of each student with a dot.

In doing that, they encountered problems with existing street lists which didn't account for alternate street names, unusual house numbers and other problems. Temple estimated that about 10 to 15 percent of all student addresses had to be hand-entered as a result.

So Robert Regan, visiting research professor at Pitt who wrote "The Steps of Pittsburgh," biked 2,000 miles through all city streets and alleys, dictating notes about the street names and numbers. The team also compared the information against other existing lists.

The result is what they believe is the most accurate database of streets and alleys yet. So as a byproduct of their works, the team is providing the street and alley list -- but not information on student addresses -- to the city and county to help emergency workers and planning.