Cartography ============ .. only:: html .. contents:: :local: :depth: 1 .. _qgiscategorizeusingstyle: Create categorized renderer from styles --------------------------------------- Sets a vector layer's renderer to a categorized renderer using matching symbols from a style database. If no style file is specified, symbols from the user's current :ref:`symbol library ` are used instead. A specified expression or field is used to create categories for the renderer. Each category is individually matched to the symbols which exist within the specified QGIS XML style database. Whenever a matching symbol name is found, the category's symbol will be set to this matched symbol. If desired, outputs can also be tables containing lists of the categories which could not be matched to symbols, and symbols which were not matched to categories. Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: any] - Vector layer to apply a categorized style to * - **Categorize using expression** - ``FIELD`` - [expression] - Field or expression to categorize the features * - **Style database (leave blank to use saved symbols)** - ``STYLE`` - [file] - File (:file:`.XML`) containing the symbols to apply to the input layer categories. The file can be obtained from the Style Manager :ref:`Share symbols ` tool. If no file is specified, QGIS local symbols library is used. * - **Use case-sensitive match to symbol names** - ``CASE_SENSITIVE`` - [boolean] Default: False - If True (checked), applies a case sensitive comparison between the categories and symbols names * - **Ignore non-alphanumeric characters while matching** - ``TOLERANT`` - [boolean] Default: False - If True (checked), non-alphanumeric characters in the categories and symbols names will be ignored, allowing greater tolerance during the match. * - **Non-matching categories** Optional - ``NON_MATCHING_CATEGORIES`` - [table] Default: ``[Skip output]`` - Output table for categories which do not match any symbol in the database. One of: * Skip output * Create Temporary Layer (``TEMPORARY_OUTPUT``) * Save to File... * Save to Geopackage... * Save to PostGIS Table The file encoding can also be changed here. * - **Non-matching symbol names** Optional - ``NON_MATCHING_SYMBOLS`` - [table] Default: ``[Skip output]`` - Output table for symbols from the provided style database which do not match any category. One of: * Skip output * Create Temporary Layer (``TEMPORARY_OUTPUT``) * Save to File... * Save to Geopackage... * Save to PostGIS Table The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Non-matching categories** - ``NON_MATCHING_CATEGORIES`` - [table] - Lists categories which could not be matched to any symbol in the provided style database * - **Non-matching symbol names** - ``NON_MATCHING_SYMBOLS`` - [table] - Lists symbols from the provided style database which could not match any category * - **Categorized layer** - ``OUTPUT`` - [same as input] - The input vector layer with the categorized style applied. No new layer is output. .. _qgistopologicalcoloring: Topological coloring -------------------- Assigns a color index to polygon features in such a way that no adjacent polygons share the same color index, whilst minimizing the number of colors required. The algorithm allows choice of method to use when assigning colors. A minimum number of colors can be specified if desired. The color index is saved to a new attribute named **color_id**. The following example shows the algorithm with four different colors chosen; as you can see each color class has the same amount of features. .. figure:: img/topological_color.png :align: center Topological colors example Parameters .......... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Input layer** - ``INPUT`` - [vector: polygon] - The input polygon layer * - **Minimum number of colors** - ``MIN_COLORS`` - [number] Default: 4 - The minimum number of colors to assign. Minimum 1, maximum 1000. * - **Minimum distance between features** - ``MIN_DISTANCE`` - [number] Default: 0.0 - Prevent nearby (but non-touching) features from being assigned equal colors. Minimum 0.0. * - **Balance color assignment** - ``BALANCE`` - [enumeration] Default: 0 - Options are: * 0 --- By feature count Attempts to assign colors so that the count of features assigned to each individual color index is balanced. * 1 --- By assigned area Assigns colors so that the total area of features assigned to each color is balanced. This mode can be useful to help avoid large features resulting in one of the colors appearing more dominant on a colored map. * 2 --- By distance between colors Assigns colors in order to maximize the distance between features of the same color. This mode helps to create a more uniform distribution of colors across a map. * - **Colored** - ``OUTPUT`` - [vector: polygon] Default: ``[Create temporary layer]`` - Specify the output layer. One of: * Skip output * Create Temporary Layer (``TEMPORARY_OUTPUT``) * Save to File... * Save to Geopackage... * Save to PostGIS Table The file encoding can also be changed here. Outputs ....... .. list-table:: :header-rows: 1 :widths: 20 20 20 40 :stub-columns: 0 * - Label - Name - Type - Description * - **Colored** - ``OUTPUT`` - [vector: polygon] - Polygon vector layer with an added ``color_id`` column