Pysld

The library is useful for generating the SLD file for raster as well as vector datasets. The package can generate the 4 types of styles,

1. Simple style
2. Categorized style
3. Classified style
4. Raster style

The library is the small version of QGIS symbology. This library is very useful for the visual appearance on the map. Below is the example of categorized style in qgis.

The package is available in official PyPI: https://pypi.org/project/pysld/

The complete documentation of this library is found here: https://pysld.readthedocs.io

Installation

pip install pysld

Some example

# Import library
from pysld.style import StyleSld

# Simple style for polygon feature
simple_sld = StyleSld(style_name='polygonStyle', geom_type='polygon', fill_color='#ffffff', stroke_color='#333333')
simple_sld_style = simple_sld.generate_simple_style()
print(simple_sld_style)

# Categorized style for polygon feature
categorized_sld = StyleSld(
            style_name='polygonStyle',
            geom_type='polygon',
            attribute_name='USE',
            values=['Agriculture', 'Residential', 'Restaurant', 'Storehouse'],
            color_palette='Spectral_r')
categorized_sld_style = categorized_sld.generate_categorized_style()
print(categorized_sld_style)

# Classified style for polygon feature
classified_sld = StyleSld(
            style_name='polygonStyle',
            geom_type='polygon',
            attribute_name='USE',
            values=[1,2,3,34,23,122,12,2,3,21,23,32,1,23,42,1,23,1,1,23,4,3,54,6,768,8,554,3,43,543,6,657,7,75,4,4],
            number_of_class=5,
            classification_method='natural_break',
            color_palette='Spectral_r')
classified_sld_style = classified_sld.generate_classified_style()
print(classified_sld_style)

# Raster style
raster_style = StyleSld(style_name='polygonStyle',color_palette='Spectral_r',continuous_legend=True)
raster_sld_style = raster_sld.generate_raster_style(max_value=100, min_value=0)

# Categorized style for PostGIS data
categorized_sld = StyleSld(
            style_name='polygonStyle',
            geom_type='polygon',
            attribute_name='USE',
            color_palette='Spectral_r',
            # Postgres connection parameters
            dbname='postgres',
            user='postgres',
            password='admin',
            host='localhost',
            port='5432',
            schema='public',
            pg_table_name='postgres_table_name')
print(categorized.values) # It will print the unique values from postgres_table_name table
categorized_style_sld = categorized.generate_categorized_style()

Generated SLD file example

Simple SLD

<StyledLayerDescriptor version="1.0.0" xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd" xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <NamedLayer>
        <Name>style</Name>
        <UserStyle>
        <Title>style</Title>
        <FeatureTypeStyle>
    <Rule>
        <PolygonSymbolizer>
            <Fill>
                <CssParameter name="fill">#ffffff</CssParameter>
                <CssParameter name="fill-opacity">1</CssParameter>
            </Fill>
            <Stroke>
                <CssParameter name="stroke">#333333</CssParameter>
                <CssParameter name="stroke-width">1</CssParameter>
            </Stroke>
        </PolygonSymbolizer>
    </Rule>
        </FeatureTypeStyle>
        </UserStyle>
    </NamedLayer>
</StyledLayerDescriptor>

Raster SLD

<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:gml="http://www.opengis.net/gml" version="1.0.0" xmlns:ogc="http://www.opengis.net/ogc" xmlns:sld="http://www.opengis.net/sld">
    <UserLayer>
        <sld:LayerFeatureConstraints>
        <sld:FeatureTypeConstraint/>
        </sld:LayerFeatureConstraints>
        <sld:UserStyle>
        <sld:Name>polygonStyle</sld:Name>
        <sld:FeatureTypeStyle>
            <sld:Rule>
            <sld:RasterSymbolizer>
                <Opacity>1</Opacity>
                <sld:ChannelSelection>
                <sld:GrayChannel>
                    <sld:SourceChannelName>1</sld:SourceChannelName>
                </sld:GrayChannel>
                </sld:ChannelSelection>
                <sld:ColorMap type="range">
                    <sld:ColorMapEntry color="#54aead" label=" 0.0" quantity="0.0"/>
                    <sld:ColorMapEntry color="#bfe5a0" label=" 25.0" quantity="25.0"/>
                    <sld:ColorMapEntry color="#fffebe" label=" 50.0" quantity="50.0"/>
                    <sld:ColorMapEntry color="#fdbf6f" label=" 75.0" quantity="75.0"/>
                    <sld:ColorMapEntry color="#e95c47" label=" 100.0" quantity="100.0"/>
                </sld:ColorMap>
            </sld:RasterSymbolizer>
            </sld:Rule>
        </sld:FeatureTypeStyle>
        </sld:UserStyle>
    </UserLayer>
</StyledLayerDescriptor>