DETROIT -

Members of community organizations in Detroit will get a lesson on how to help the city fight blight.

Demonstrations are planned Tuesday morning on using a smartphone app to contribute photos and updated information about derelict properties to a mapping database.

A digital map of Detroit shows the city's 380,000 real estate parcels. Teams using software did block-by-block surveys of houses, buildings, fields and lots in Detroit over the winter months.

The city will use the data to help in its plans to demolish vacant and dangerous houses and buildings.

A blight removal task force has said about 73,000 of the city's 85,000 blighted parcels are residential structures. It also said the cost to remove all neighborhood blight in Detroit could reach $850 million.