Newfoundland Labrador 1:2500 Community Mapping

Surveys and Mapping Division

Background
Eastcan has supplied Community Mapping support to the Surveys and Mapping Division of Newfoundland Labrador for the past 5 years. The projects have been located in various communities across the province. The air photos and adjustment are supplied by the client with Eastcan providing the photogrammetric data collection and topological edits to the vector data. To date Eastcan has created approx. 300 map tiles.

Project Workflow
Eastcan provides planimetric data collection using softcopy workstations running Cardinal Systems’ VR software. The input images were oriented using the AT adjustment data supplied by the client. Collection included full planimetric and surface features. Surface data included an array of spot heights, collected at 20 meter intervals and supplemented by strategic spot elevations and breaklines. The surface data was used to generate 2 meter contours. Planimetric data capture included all features visible on the 1:12,500 photography.

Quality Control
Contours were generated for each model during collection of the surface data. The raw contours were checked for ‘fit’ to the ground. Contours floating above, or digging into, the ground were corrected with additional spot elevations or breaklines to ensure and accurate representation of the ground surface.

The content of the data collection was checked using raw rectified images. Each photo was rectified with the new surface data and used for checking the completeness of the data collection. Missing features were flagged and returned for photogrammetric insertion. Vector topology was checked using ArcGIS.

Final Deliverables
The data was delivered in DXF format for conversion to ESRI format by the client. Delivery includes individual files for each map sheet.