The MapType Class

API docs

Introduction

Each map type of an autoMaps project needs to consist of:

• a MapType object (described here)
• a generator class (a subclass of MapGenerator) (see this section)
• one or more QGIS print layouts in an associated QGIS project file (see this section)

Description

A MapType object is initialized with the following arguments:

• name (str): Name of the map type. The name will be shown as main heading in the UI. It is also used to generate the radio button values for the available map types in the sidebar.

• description (str): Description of the map type. Will be displayed in the frontend.

• ui_elements (Iterable[Union[MultiSelector, BaseSelector, Tuple[Callable, str]]): Iterable of UI elements, being either selector objects or tuples of st.write and a string, e.g. (st.write, "## heading").

  • Selector objects are used to define the choices that are displayed in the UI. The selection will be stored in the associated MapGenerator object in the self.data attribute.
  • Tuples of the type (st.write, str) can be used to display texts in the UI, e.g. to display headings or further explanations.

• print_layout (Union[str, Tuple[str, Dict[str, str]]): This argument connects the MapType with on or more QGIS print layouts. print_layout must take one of the following two types:

  • str: The name of the print layout in the associated QGIS project.
  • tuple[str, Dict[str, str]]:
    • At position 0 of tuple: The name of the selector, from which the name of the print layout is to be read.
    • At position 1 of the tuple: A mapping between the options of the selector and the corresponding names of the print layout. Example:

    print_layout=
        (
            "map layout",  # the name of the selector, as defined in `ui_elements`
            {
                "external": "Public transport overview [external]",
                "internal": "Public transport overview [internal]",
                "reduced": "Public transport overview [reduced]"
            }
        )

• map_generator (Type[MapGenerator]): The class of the associated MapGenerator. This generator receives the data dictionary from the frontend, containing all the user selections plus additional metadata, and creates the map based on this input.

• html_beneath_name (str, optional): This string can be used, to add arbitrary html code in the UI, right beneath the MapType name heading (e.g. to add custom links to a help page).

Example

import streamlit as st

from automaps.maptype import MapType
from automaps.selector import SelectorSimple, SelectorSQL
from generate_poly import MapGeneratorPoly

maptype_poly = MapType(
    name="Districts in Vienna",
    description="Choose a district and get your map!",
    ui_elements=[
        SelectorSQL(
            "District name",
            """
            select distinct NAMEK
            from districtborder
            order by NAMEK""",
            st.selectbox,
            widget_args={"help": "Choose your district!"},
            no_value_selected_text="Choose district ...",
        ),
        SelectorSQL(
            "Stop names,
            """
            select distinct name
            from stops
            where district = '{{ data["District name"] }}'
            order by name""",
            st.multiselect,
            widget_args={"help": "Choose the stops to be displayed!"},
            depends_on_selectors=["District name"],
            no_value_selected_text="Choose stops ...",
        ),
        SelectorSimple(
            "File Format",
            ["PDF", "PNG", "SVG"],
            st.radio,
            exclude_from_filename=True,
            use_for_file_format=True,
        ),
    ],
    print_layout="poly",
    map_generator=MapGeneratorPoly,
)

MAPTYPES_AVAIL = [maptype_poly]