Georeferencer is a tool that will allow you to transform a picture into a map.
When you scan an aerial photograph or import a satellite image, you have a picture in a
coordinate system that has no relation to earth location. You might be able to generally
relate the picture to a corresponding area on the earth but you can not know the details
of this correspondence- namely, the geographic location of every point (pixel) in the
image. Your computer knows even less.
Getting a digital image into a geographic data processing system requires building a
relation between the abstract coordinate geometry of the image and real earth geometry.
The process through which this construction and transformation is performed is called
georeferencing.
Georeferencing is a simple undertaking. All you need is a knowledge of the exact location
on earth of at least four features that are in plain view in the image. This knowledge can
come from a GPS survey of points or it can be developed by comparing features in the
picture with the same features in a georeferenced digital image or drawing. We developed
Pocket DLog as a GPS-based system for mapping that features navigation on
georeferenced image backdrops. These points of comparison between a non-georeferenced
picture and a georeferenced image, drawing or data entry are called Control Points.
Control points are used in an equation that predicts the position that a point in an
abstract, "file" space will have in a new "map" space. A picture can
have thousands or millions of points (pixels). Georeferencer operates on each point.
Download
GeoReferencer v7.0.0.10
