HARRISBURG — Pennsylvanians who want to participate in the once-a-decade redrawing of state legislative districts will get a chance this year through a website that will eventually show how the new map is taking shape.

The state Legislative Reapportionment Commission is expected to approve the website at its meeting today, and it should be online by the end of this week, according to an official familiar with the project who spoke on the condition of anonymity because he was not authorized to discuss it publicly.

The panel, made up of the four Republican and Democratic legislative floor leaders, is charged with reshaping House and Senate districts to ensure equal representation at the Capitol following population shifts of the past decade.

Users of the interactive website will be able to compare the current House and Senate districts, which are based on the 2000 census, with the previous districts that were based on the 1990 census and, ultimately, with the new districts based on the 2010 census. Clicking on a district will reveal its 2000 and 2010 population, its voting population and its racial makeup, the official said.

Activists and others interested in drawing their own district maps for consideration can obtain the detailed precinct-level data they need, and Pennsylvanians who want to express opinions or send documents to the commission can do so quickly through the website.

The five-member panel, chaired by Superior Court Senior Judge Stephen McEwen, is expected to officially start the months-long redistricting process by certifying the census numbers. It also is expected to schedule public hearings.

The constitutionally mandated commission has been appointed once a decade since the 1970 census. All of four plans approved by previous commissions survived court challenges.

The commission’s work is being closely scrutinized by legislators whose careers may be helped or hurt by changes in their districts, but it also could affect many citizens who are used to working with and being represented by their senator or representative.

“There’s a chance they’re going to have a new representative, a new senator and possibly a new congressman,” said Steve Miskin, spokesman for House Majority Leader Mike Turzai, R-Allegheny.

The redrawing of Pennsylvania’s U.S. House districts, while similar to the state legislative redistricting, is achieved through a separate process in which the proposed changes must be approved by the Legislature and the governor.