Visual Interpretation Skills How to read a satellite image

What do you need to interpret remotely sensed imagery? Familiarity with the specific area or similar areas Basic interpretation skills Image prints that are of sufficient quality Projection grid marks on the image are helpful to locate oneself on the image using a GPS Equipment to protect the imagery if working in the field Tools to transcribe information onto the image

Basic Elements of Visual Interpretation Tone (color) Size and shape Texture and pattern Relative and absolute location Shadows

Tone and Color Variations in tone and color results in all of the other visual elements When looking at a image photo we associate specific tones to particular features Tones change when we enhance an image or when we change the band combination of a color image

Size and Shape Rectilinear and circular features often indicate human influence such as agriculture Size and shape information greatly influenced by image resolution Knowing the scale of the image helps to convert image feature dimensions to actual dimensions

Texture and Pattern Varies with image resolution Often noted by roughness or smoothness Influenced by shadows

Relative and Absolute Location The location of a feature narrows the list of possible cover types Relative location particularly useful to determine land use

Shadows Often considered a contaminant but can be very useful to identify features on an image Helpful to accentuate relief Shadow effects change throughout the day and throughout the year Shadows can give an indication to the size of a particular feature