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4What are the seven elements used by geoarchaeologists to analyze and interpret remotely sensedimages?Geoarchaeologists face several issues when using remotely sensed images. They must determine thelocation on Earth, the height of objects, the scale of the image (based on the distance and the angle fromwhich the image was sensed), and what the images show from the size and resolution of the image.These skills are similar to those used in reading a map. Perhaps the most important skill is analyzing thecolors and patterns on a remotely sensed image.Identifying Detail on Remotely Sensed ImagesSeven interpretive elements help geoarchaeologists analyze an image:• tone• shape• size• pattern• texture• shadow• associationBelow are descriptions and examples of each element, followed by several questions to help you focuson what you see.1TONEis the brightness or the color of objects in animage. It is a very important element in distinguish-ing target objects.* Different types of imaging(radar, infrared, photographic) record differenttypes of energy reflected or emitted by the target.Whether true color, as on a photograph, or falsecolor imaging, a target stands out.*A target object is the geographic feature thegeoarchaeologist is looking for, like a road or abuilding.List the tones (colors) on this image.Which tone is the brightest?What do you think this bright color is showing?Chaco Canyonhttp://www.ghcc.msfc.nasa.gov/archeology/chaco_compare.htmlModule 4, Investigation 2: Log 1What features do archaeologists look for on an image?5SHAPEis the general form or outline of an object in animage. Shape helps distinguish an object. Mosthuman-made objects have regular geometricshapes and edges, such as roads, buildings, andagricultural fields. Natural features typically havean irregular shape, such as a forest or a naturallake, although some natural features such asglacially formed lakes have fairly regular shore-lines.List geometric shapes in this image:What do you think is being shown by the shapes?SIZEof a target object relates to scale. Object size canbe compared and measured using shadow lengthof known features. Size of objects is related to thedistance from which the image is sensed and thetype of sensor used.The lines crossing the aureole (circle) are automo-bile tracks.Using this information, determine the width of theroad that crosses the photo from left to right. Circlewhich size tracks that you think that they are:automobile trackstwo-lane unpaved roadfour-lane highwayWhat is the line connecting the homestead (in theupper right corner) with the road?2Ankgor, Cambodiahttp://www.jpl.nasa.gov/radar/sirsxsar/angkor.htmlAureole of Chacoan Culturehttp://www.nmia.com/~jaybird/AANewsletter/ChacoPage2.html Used with permission T. BakerModule 4, Investigation 2: Log 1What features do archaeologists look for on an image?63PATTERNis the spatial arrangement of objects in an image.An arrangement of lines or objects regularlyspaced, such as streets in a city, is a pattern.The Euphrates River is the dark thick line whichflows through the center of this photograph. On theleft side of the river, the drainage branches form apattern known as dendritic. Look carefully to noticethat the “little branches” all flow into another branchwhich eventually flows into the Euphrates River.This pattern is associated with what type of physi-cal geographic feature?On the right side of the Euphrates River is a morerectangular pattern. What do you think this patternshows?TEXTURErefers to the pattern and tones in an image.Rough textures reflect energy and produceirregular, uneven images. This might be the top ofa rain forest where trees are not the same height,a mountainous region, or soil with differentamounts of water content. Smooth textures havesurfaces with similar objects evenly mixed, suchas a field of wheat, a parking lot, or grasslands.Texture is one of the most important elements inanalyzing radar imagery.Euphrates River and Zeugma, Turkeyhttp://www.ist.lu/ele/html/department/zeugma/html/maps/gis1.htmlDeforestation in the Petén, Guatemalahttp://www.ghcc.msfc.nasa.gov/archeology/peten.htmlThis image of the Petén has a very straight edge on it. In Guatemala, the Petén is a protected rain forest.In Mexico, land has been cleared of rain forest.What vegetation does the darker texture show: rain forest or cleared land?What vegetation does the lighter texture show?Module 4, Investigation 2: Log 1What features do archaeologists look for on an image?74SHADOWis produced by the angle of the Sun and theangle of the equipment recording the image.A slightly oblique (side) view of a site oftenproduces a shadow. Shadows are used todetermine heights of objects.Pyramids at Giza, Egypthttp://ourworld.compuserve.com/homepages/mjff/giza_kvr.htmThis photograph was taken at an oblique angle. The shadows on the target objects clearly show that theyare _________________ .If you looked at the pyramids from directly above they would appear as what shape?Because this photograph is taken at a slightly oblique view, you clearly see that these three main pyra-mids have __________ sides, each with a _________________ shape.Using the shadow as a guide, which pyramid is the tallest?Module 4, Investigation 2: Log 1What features do archaeologists look for on an image?85ASSOCIATIONis the relationship between recognizable objectsand unrecognizable objects. Making an associa-tion allows the identification of objects which, bythemselves, would not be recognized in an image.For example, many schools have playgrounds orball fields. If the school building is recognizable,then the patch of ground near it can be identified.The reverse is also true—ball fields and parkinglots may be used to identify a school building.The dark area in the southwest corner is TonleSap, a lake in Cambodia. If we know that thissmooth textured dark color is water, we mayidentify other water bodies on this image. Lookcarefully at the left center of the image. There is alarge dark rectangle. We now associate thistexture and tone with the lake.Angkor, Cambodiahttp://jpl.nasa.gov/radar/sircxsar/angkor.htmlThe large dark rectangle isNear this rectangle are two more similar thick lines of similar tone and texture. One looks like an L; theother is a dark line around a light-colored square.These are alsoAre these three features natural or human made?(Remember that natural features are usually irregular and that human-made features often


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