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tutorial5 - Section5: BufferingFeatures ....

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University of Arkansas Libraries ArcGIS Desktop Tutorial (http://libinfo.uark.edu/gis/tutorial.asp) Section 5 Page 1 Section 5: Analyzing Spatial Data Buffering Features: A buffer operation is one of the most common spatial analysis tools. A buffer is a map feature that represents a uniform distance around a feature. When creating a buffer, the user selects the feature to buffer from, as well as the distance to be buffered. The buffer operation creates a new polygon data set, where a specified distance is drawn around specific features within a layer. The distances can either be constant or can vary depending upon attribute values. When features are close together, their buffers may overlap. The user can choose to preserve the overlaps or remove them. To use the ArcToolbox Buffer tool, the user must go to Analysis Tools and select Proximity. Buffer then appears in the list of tools. A double click on Buffer results in the appearance of the Buffer dialog box. The drop down arrow should be clicked, or the browse button used, to select the layer the user wishes to buffer. Then, the Linear unit radio button should be clicked and units and distance specified. If the user wishes to dissolve the barriers between any overlapping buffers he or she may do so by selecting LIST from the drop down menu within Dissolve Type . Once the list of attribute fields appears with a white background the box next to Shape should be checked.
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University of Arkansas ArcGIS Desktop Libraries Tutorial (http://libinfo.uark.edu/gis/tutorial.asp) Section 5 Page 2 If the user wants to create a buffer around an input feature he or she may specify a value as illustrated above or a numeric field in the attribute table can be specified using the Field radio button. The OK button should be clicked once all parameters have been set. The buffer will be created and added to the ArcMap display if ArcToolbox was opened through ArcMap. Once a buffer has been created the user may want to add the buffer distance to the new layer's attribute table. This can be done by right clicking on the layer name in the table of contents and selecting Open Attribute Table . Once the attribute table opens, the Options button should be clicked. The user should then select the Add Field option.
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University of Arkansas Libraries ArcGIS Desktop Tutorial (http://libinfo.uark.edu/gis/tutorial.asp) Section 5 Page 3 When the Add Field Dialog Box appears, the user must type in the name of the new field, select the type of attribute that will be added to the field, and click OK . In the above, a new field was created called "BufferDist" that will contain numeric data, in this case "25" for 25 miles buffer distance. Once a new field has been created the user can place values in the cells under "BufferDist" by going to Tools on the main menu and selecting Editor Toolbar followed by Editor on the toolbar and then Start Editing . With this preparation the contents of cells in an attribute table may be edited simply by placing the cursor in the cell(s) and typing
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  • Spring '10
  • Arshad
  • University of Arkansas, Libraries  ArcGIS Desktop, ArcGIS Desktop Tutorial, Arkansas Libraries  ArcGIS

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