Leica Photogrammetry Suite Project Manager

Image Space Coordinate SystemAn image space coordinate system is identical to an imagecoordinate system, except that it adds a third axis (z) to indicateelevation. The origin of the image space coordinate system is definedat the perspective center S as shown in Figure 10. The perspectivecenter is commonly the lens of the camera as it existed when thephotograph was captured. Its x-axis and y-axis are parallel to the x-axis and y-axis in the image plane coordinate system. The z-axis isthe optical axis, therefore the z value of an image point in the imagespace coordinate system is usually equal to -f (the focal length of thecamera). Image space coordinates are used to describe positionsinside the camera and usually use units in millimeters or microns.This coordinate system is referenced as image space coordinates (x,y, z) in this chapter.Figure 10: Image Space and Ground Space Coordinate SystemzyImagecoordinatesystemSxfaoZHeightYAGroundcoordinatesystemXGround Coordinate SystemA ground coordinate system is usually defined as a 3D coordinatesystem that utilizes a known geographic map projection. Groundcoordinates (X,Y,Z) are usually expressed in feet or meters. The Zvalue is elevation above mean sea level for a given vertical datum.This coordinate system is referenced as ground coordinates (X,Y,Z)in this chapter.LPS Project ManagerImage and Data Acquisition / 26