Rebuilt 3D topographic map base saves city $7 million to date, supports city services and provides data to outside users.

When the present-day City of Toronto was consolidated from seven municipalities in 1998, a number of challenges were created by this immense amalgamation.

Central to these challenges was rebuilding the topographic map base, which is the basis for many city services such as sewer design and construction and urban planning.

Together with his staff, Bob Gaspirc, manager of the city’s Survey and Mapping Services group, met the task head-on.
Progress from change

Fortunately, the amalgamation had its benefits as well as its challenges. According to Gaspirc, the inevitable review of redundant work processes allowed the city to introduce new methodologies and ideas regarding how topographic information could be collected.
As a result, the group created an environment called the Enterprise Stereoscopic Model (ESM), which allowed it to rebuild the topographic mapping base, generate high-resolution orthoimagery and develop spinoff products for other entities.

Through the use of 3D modelling within the ESM, applications such as terrain modelling, watershed modelling, stormshed management and emergency management planning are enhanced by visualisation that allows users to see the physical reality of their work sites.

The ESM environment consists of two major components: an aerial image vectorisation application from DVP Stereo Systems, combined with Bentley’s MicroStation GeoGraphics software. At a photogrammetric workstation, the aerial imagery, which has a resolution of 7.5 centimeters and is sharp enough to view objects as small as fire hydrants, is viewed in 3D. Elements are vectorized using image vectorisation software.