Cartographic generalization
Merge
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''Also called dissolve, amalgamation, agglomeration, or combine'' |
''Also called dissolve, amalgamation, agglomeration, or combine'' |
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This operation, identified by Imhof in 1937, involves combining neighboring features into a single feature of the same type, at scales where the distinction between them is not important. For example, a mountain chain may consist of several isolated ridges in the natural environment, but shown as a continuous chain on a small scale the map. Or, adjacent buildings in a complex could be combined into a single "building." For proper interpretation, the map reader must be aware that because of scale limitations combined elements are not perfect depictions of natural or manmade features.{{Cite journal |last=Raveneau |first=Jean |date=1993 |title=[Review of] Monmonier, Mark (1991) How to Lie with Maps. Chicago, University of Chicago Press, 176 p. ({{Text|ISBN}} 0-226-53415-4)|journal=Cahiers de Géographie du Québec |volume=37 |issue=101 |page=392 |doi=10.7202/022356ar |issn=0007-9766|doi-access=free }} Dissolve is a common GIS tool that is used for this generalization operation,{{Cite web|url=http://pro.arcgis.com/en/pro-app/tool-reference/data-management/h-how-dissolve-data-management-works.htm|title=How Dissolve (Data Management) Works |website=ArcGIS Desktop |access-date=2018-12-13}} but additional |
This operation, identified by Imhof in 1937, involves combining neighboring features into a single feature of the same type, at scales where the distinction between them is not important. For example, a mountain chain may consist of several isolated ridges in the natural environment, but shown as a continuous chain on a small scale the map. Or, adjacent buildings in a complex could be combined into a single "building." For proper interpretation, the map reader must be aware that because of scale limitations combined elements are not perfect depictions of natural or manmade features.{{Cite journal |last=Raveneau |first=Jean |date=1993 |title=[Review of] Monmonier, Mark (1991) How to Lie with Maps. Chicago, University of Chicago Press, 176 p. ({{Text|ISBN}} 0-226-53415-4)|journal=Cahiers de Géographie du Québec |volume=37 |issue=101 |page=392 |doi=10.7202/022356ar |issn=0007-9766|doi-access=free }} Dissolve is a common GIS tool that is used for this generalization operation,{{Cite web|url=http://pro.arcgis.com/en/pro-app/tool-reference/data-management/h-how-dissolve-data-management-works.htm|title=How Dissolve (Data Management) Works |website=ArcGIS Desktop |access-date=2018-12-13}} but additional tools have been developed for specific situations, such as finding very small polygons and merging them into neighboring larger polygons. This operator is different from aggregation because there is no change in dimensionality (i.e. lines are dissolved into lines and polygons into polygons), and the original and final objects are of the same conceptual type (e.g., building becomes building). |
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===Aggregate=== |
===Aggregate=== |
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