====== Dissolve Wizard ======

The Dissolve Wizard dialog is used to simplify a group of features. Dissolving is a process by which multiple features are combined into a single feature if they have matching values in the column(s) you specify. 


This dialog consists of 4 steps:  
  * Step 1 - Choose the Layer to Dissolve
  * Step 2 - Choose Which Columns to Match
  * Step 3 - Select Which Data to Include
  * Step 4 - Save the Results

===== Video Overview =====
{{youtube>HmkoQcSEGNw?720|Using the Dissolve Wizard.}}


===== Step 1 - Choose the Layer to Dissolve =====
Step 1 of the Dissolve Wizard allows users to select which layer to dissolve.  The **Layer** select box displays all layers available in the current project.  After selecting a layer, the user can then press the **Next** button.   

If your layer has certain features that have been selected on the **Select Features** tab, you may also check the **Only dissolve the currently selected features on this layer** checkbox.

===== Step 2 - Choose Which Columns to Match =====
Step 2 of the Dissolve Wizard allows users to select which **Columns to Match**.  Only the features that have matching values in all of the columns that you specify will be dissolved together.  You may select one or more columns in this step.  There is also a **View Data** button in this step that allows you to view the layer's tabular data and determine the best column(s) to match.

===== Step 3 - Select Which Data to Include =====
In addition to the columns you selected in step 2, Step 3 allows you to add additional columns to be included in  your final output layer.  The additional columns are a combination of a column from the original data and an **Operator** which will select how you want the data added or aggregated.  

**Operator** - This select box determines how the value for the output feature is calculated.  Below is a description of the operator options:
  * **First** - Takes the value of the column from the first feature that is dissolved.
  * **Last** - Takes the value of the column from the last feature that is dissolved.
  * **Count** - Counts the total number of unique values in this column amongst all of the dissolved features.
  * **Sum** - Adds together all of the values in the column amongst all of the dissolved features.  For numerical data only.
  * **Average** - Averages all of the values in this column amongst all of the dissolved features.  For numerical data only.
  * **Min** - Uses the minimum value found for this column amongst all of the dissolved features.  For numerical data only.
  * **Max** - Uses the maximum value found for this column amongst all of the dissolved features.  For numerical data only.

There is also another **View Data** button that allows you to view the layer's tabular data to determine which data to include. 

===== Step 4 - Save the Results =====
Like other Tools wizards, this step allows users to choose how they want the wizard results to be saved.  Users can choose to **Add to Map** and specify the desired layer name, or choose to **Output to File**.  If **Output to File** is chosen, the user must select an existing or new file to save the results into.