How to georeference a bitmap? Help/FAQ Geoinformation/Geodata Information Map Projection Geodetic Reference System
8.October 1998
Bitmaps and Raster data
  • There exist different types of two-dimensional raster data with different semantics:
    • raster element represents a point: vertex (e.g. for digital terrain models)
    • raster element represents an area: pixel (e.g. raster images, graphics, scanned documents, bitmaps)
  • In the most cases, raster elements are aligned in rowsand columns with equal spacing in rows and columns
  • raster data are referenced to a raster coordinate system (coordinates are described by number of row and column, as integer or real numbers (for measuring subpixels)
  • the origin of raster coordinate systems vary:
    • vertex coordinate systems: first element for row and column: 0 or 1
    • pixel coordinate systems: origin at the border or in the centre of the pixel, = offset of 0.5 pixel
  • raster coordinates have no units
  • metrics of raster coordinates are derived by defining the spacing distance for rows and columns
Georeferencing a Bitmap
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GeoTIFF
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