Image Interpretation Web-based GIS workshop for teachers September 19, 2009.
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Transcript of Image Interpretation Web-based GIS workshop for teachers September 19, 2009.
Where Do Images Come From?
• Aircraft– Aerial photos
• Satellites– Satellite imagery
Courtesy of the California Coastal Records Project
Source: Google Earth
Shape
Man-made features tend to have straight edges; natural features do not
Which one of these is a river and which one is a canal?
Size
The size of an object can help you determine what it is.
Which is the school complex and which are the houses?
Pattern
Certain objects have distinct patterns. Man-made features tend to have regular patterns while natural features tend to have irregular patterns.
San Francisco
Mountain drainage patterns
Tone/Color
The brightness and variation of color can help you interpret the image.This image shows various types of agricultural crops.
Association
Sometimes you can identify an object by what is surrounding it.
Which image is a mountain lake and which is a high desert lake?Which one is Lake Tahoe?
Spatial Resolution
• How much detail you can see on the ground
1m spatial resolution(Digital Globe and others)
30 m spatial resolution(Landsat Thematic Mapper)