|
MapRef-Home
>
FAQ - Frequently Asked Questions
>
How to georeference a bitmap?
|
back
next 
|
|
|
|
|
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
|
|
|
|
|
related information
