giv, The G(reat|tk|NU) Image Viewer, is an image and vector overlay viewer.

Features:
* Based on the gtk_image_viewer widget and can thus deal with huge images at large zoom ins.
* Defines a simple ascii-based format for drawing vector overlays on top of the image. Great for Vision application.
* The display of datasets are highly customizable including line widths, marks, color names according to x11 database, hierarchical paths.
* Easily deals with vector sets of several million vectors.
* User defined popups when the mouse hovers over a dataset.
* A tree based dataset viewer for turning on and off the display of part of the vector data.