GIS Files 2: Geographical data

2.1: Data capture from maps (3)

Vectorisation

Some very specialised computer systems are able to convert raster data to vector data by recognising patterns in the image. For instance, it can guess that a sequence of coloured pixels which seem to form a line across the image are showing a linear feature of some kind. If the system knows the extent of the real position of the image, it can convert these shapes into vector information. This vectorisation from raster data can be a fast method of capture because it can be automated, but is usually less accurate than manual digitising.

Now we will look at more direct methods of obtaining geospatial data, in section 2.2 – Surveying and remote sensing.

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