Paper
1 August 1991 Automatic digitization of contour lines for digital map production
Juha Yla-Jaaski, Xiaohan Yu
Author Affiliations +
Abstract
Methods are described for an automated recognition of height contours from graphic maps. The methods are applied to a large-scale conversion of contour data into digital format. Two data structures are used during the recognition process. The actual contour data is fully described by a line structure obtained by vectorizing the thinned medial axis of the original scanned contours. A second line structure is obtained by applying a similar procedure for the background of the image. This process yields a vectorized medial axis of the background consisting of so-called dual lines. By definition, each dual line represents a neighborhood relation between two contour line segments. The recognition of the contours consists of two phases. Closed height contours are first constructed from broken contour segments followed by attaching absolute height labels to the recognized contours. The formation of closed contours relies on a knowledge-based algorithm which utilizes both attributes of actual contour line segments and their inter-relations described by the dual lines. The dual lines are also valuable when attaching height labels on the contours.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Juha Yla-Jaaski and Xiaohan Yu "Automatic digitization of contour lines for digital map production", Proc. SPIE 1472, Image Understanding and the Man-Machine Interface III, (1 August 1991); https://doi.org/10.1117/12.46485
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KEYWORDS
Image segmentation

Data conversion

Image understanding

Raster graphics

Image processing

Detection and tracking algorithms

Visualization

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