Features with the same value combinations for the specified fields will be aggregated dissolved into a single feature. Dissolve may result in multipart features being created.
A multipart feature is a single feature that contains noncontiguous elements and is represented in the attribute table as one record. The state of Hawaii is a common example of a feature represented as a multipart feature. This limitation could cause an error to occur, as the dissolve process may require more memory than is available.
To prevent this, Dissolve may divide and process the input features using an adaptive tiling algorithm. To determine the features that have been tiled, run the Frequency tool on the result of this tool, specifying the same fields used in the dissolve process for the Frequency Field s parameter.
Any record with a frequency value of 2 has been tiled. Tile boundaries are preserved in the output features to prevent the creation of features that are too large to be used by ArcGIS. Running Dissolve on the output of a previous dissolve run will rarely reduce the number of features in the output when the original processing divided and processed the inputs using adaptive tiling.
The maximum size of any output feature is determined by the amount of available memory at run time; therefore, output containing tiles is an indicator that dissolving any further with the available resources will cause an out-of-memory situation or result in a feature that is unusable. Additionally, running the Dissolve tool a second time on output that was created this way may result in very slow performance for little to no gain and may cause an unexpected failure. The Unsplit lines parameter only applies to line input.
When the default is specified, lines are dissolved into a single feature; otherwise, only two lines that have a common endpoint known as a pseudonode are merged into one continuous line. The feature class to be created that will contain the aggregated features. The field or fields on which to aggregate features. Specifies the numeric field or fields containing the attribute values that will be used to calculate the specified statistic. Multiple statistic and field combinations can be specified.
Text attribute fields can be summarized using first and last statistics. Numeric attribute fields can be summarized using any statistic. Specifies whether multipart features are allowed in the output feature class. The following Python window script demonstrates how to use the Dissolve function in immediate mode.
The following stand-alone script demonstrates how to use the Dissolve function. Feedback on this topic? Back to Top. Summary Aggregates features based on specified attributes. Usage The attributes of the features that become aggregated by dissolve can be summarized or described using a variety of statistics.
Caution: Running Dissolve on the output of a previous dissolve run will rarely reduce the number of features in the output when the original processing divided and processed the inputs using adaptive tiling. This is the default. Dissolve is an application of the conceptual operators that aggregates features often referred to as 'Merge' or 'Amalgamation. In choropleth maps, the dissolve operation eliminates the boundaries of enumeration units with a common value, depicting a much larger area holding the same common value.
Thus, using the dissolve operator on multiple polygons with a common value will yield one new polygon, combining the dimensions of the original, dissolved polygons. Giving linear features a dotted appearance or connecting linked line segments into one larger line segment in a GIS is also considered a dissolve operation.
Dissolve has various applications in cartography and GIS. For example, road or river datasets often present the same linear feature in a number of segments. This can create problems for analysis or display, but dissolve can be used to combine them together and facilitate their intended use. Polygons are also commonly dissolved. For example, a cartographer or GIS user may desire to show several distinct polygon areas as one contiguous area, such as combining certain areas into one large region for instance, merging east and west Germany into Germany.
The dissolve operation is useful for performing these and many other tasks which a cartographer or GIS user may encounter.
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