This site from Malin Space Science Systems provides links to a large fraction of images taken by the Viking orbiters from 1976 to 1980. These images have a resolution of 400 meters/pixel or better and an emission angle (angle between the surface normal at the center of the image and the vector to the spacecraft) of less than 45 degrees. At present there are about 33,500 images available.
Subject: Geoscience:Lunar and Planetary Science:Mars:Images/Maps/Visualizations, Geoscience:Geology:Structural Geology:Structural Visualizations, Geoscience:Lunar and Planetary Science:Mars:Missions/Data Acquisition, Geography:Geospatial Resource Type: Scientific Resources:Collection, Audio/Visual:Images/Illustrations, Datasets and Tools:Datasets Theme: Teach the Earth:Course Topics:Structural Geology, GIS/Remote Sensing, Planetary ScienceKeyword: geospatial data
