Managers

When creating applications using the Tethys Workflows Extension, you'll often need a Map Manager class and a Spatial Manager class. This documentation will provide help on creating those files.

Map Manager

Map Managers help us prepare and configure the interactive maps used in workflows. The best way to build a map manager class is to build on the MapManagerBase class included in the Workflows Extension.

To do so, you'll need the following imports:

from tethys_gizmos.gizmo_options import MapView, MVView
from tethysext.workflows.services.map_manager import MapManagerBase

Methods:

__init__(self, spatial_manager)

• Description: Initializer used for the Map Manager class.
• Parameters:
  • spatial_manager(tethysext.workflows.services.base_spatial_manager.BaseSpatialManager): the spatial manager class assigned to this map manager

compose_map(self, request, *args, **kwargs)

• Description: Abstract method to be overriden to prepare the map with any desired layer(s)
• Parameters:
  • request(HttpRequest): A Django request object.
• Returns:
  • MapView object
  • extent
• Example:

  def compose_map(self, request):
      layers = []
      layer_groups = []
  
      with open('/path/to/geojson_file', 'r') as geojson_file:
          geojson_data = geojson_file.read()
      geojson_layer = self.build_geojson_layer(geojson_data, "GeoJSON Layer Name", "GeoJSON Layer Title", "geojson_layer_var", "geojson_layer_id")
      layers.append(geojson_layer)
  
      layer_group = self.build_Layer_group("layer_group_id", "GeoJSON Layers", layers)
      layer_groups.append(layer_group)
  
  
      map_view = MapView(
          height='600px',
          width='100%',
          controls=['ZoomSlider', 'Rotate', 'FullScreen'],
          layers=layers,
          view=MVView(
              projection='EPSG:4326',
              center=self.DEFAULT_CENTER,
              zoom=13,
              maxZoom=28,
              minZoom=4,
          ),
          basemap=['ESRI', 'OpenStreetMap',],
          legend=True
      )
  
      _, extent = self.get_map_extent()
  
  
      return map_view, extent, layer_groups

get_cesium_token(self)

• Description: Get the cesium token for Cesium Views (meant to be overriden with actual cesium API token)
• Returns:
  • token(str): the cesium API token

build_param_string(self, **kwargs)

• Description: Build a VIEWPARAMS or ENV string with given kwargs (e.g.: 'foo:1;bar:baz')
• Parameters:
  • kwargs: key-value pairs of paramaters
• Returns:
  • param_string(str): parameter string

build_geojson_layer(self, geojson, layer_name, layer_title, layer_variable, layer_id='', visible=True, public=True, selectable=False, plottable=False, has_action=False, extent=None, popup_title=None, excluded_properties=None, show_download=False, label_options=None)

• Description: Build a GeoJSON MVLayer object with supplied arguments

• Parameters:

  • geojson(dict): Python equivalent GeoJSON FeatureCollection.
  • layer_name(str): Name of GeoServer layer (e.g.: agwa:3a84ff62-aaaa-bbbb-cccc-1a2b3c4d5a6b7c8d-model_boundaries).
  • layer_title(str): Title of MVLayer (e.g.: Model Boundaries).
  • layer_variable(str): Variable type of the layer (e.g.: model_boundaries).
  • layer_id(UUID, int, str): layer_id for non geoserver layer where layer_name may not be unique.
  • visible(bool): Layer is visible when True. Defaults to True.
  • public(bool): Layer is publicly accessible when app is running in Open Portal Mode if True. Defaults to True.
  • selectable(bool): Enable feature selection. Defaults to False.
  • plottable(bool): Enable "Plot" button on pop-up properties. Defaults to False.
  • has_action(bool): Enable "Action" button on pop-up properties. Defaults to False.
  • extent(list): Extent for the layer (optional)
  • popup_title(str): Title to display on feature popups. Defaults to layer title.
  • excluded_properties(list): List of properties to exclude from feature popups.
  • show_download(boolean): enable download geojson as shapefile. Default is False.
  • label_options(dict): Dictionary for labeling. Possibilities include label_property (the name of the property to label), font (label font), text_align (alignment of the label), offset_x (x offset) (optional)

• Returns: mv_layer(MVLayer): the layer object

build_cesium_layer(self, cesium_type, cesium_json, layer_name, layer_title, layer_variable, layer_id='', visible=True, public=True, selectable=False, plottable=False, has_action=False, extent=None, popup_title=None, excluded_properties=None, show_download=False)

• Description: Build a cesium MVLayer object with supplied arguments.
• Parameters:
  • cesium_type(enum): 'CesiumModel' or 'CesiumPrimitive'.
  • cesium_json(dict): Cesium dictionary to describe the layer.
  • layer_name(str): Name of GeoServer layer (e.g.: agwa:3a84ff62-aaaa-bbbb-cccc-1a2b3c4d5a6b7c8d-model_boundaries).
  • layer_title(str): Title of MVLayer (e.g.: Model Boundaries).
  • layer_variable(str): Variable type of the layer (e.g.: model_boundaries).
  • layer_id(UUID, int, str): layer_id for non geoserver layer where layer_name may not be unique.
  • visible(bool): Layer is visible when True. Defaults to True.
  • public(bool): Layer is publicly accessible when app is running in Open Portal Mode if True. Defaults to True.
  • selectable(bool): Enable feature selection. Defaults to False.
  • plottable(bool): Enable "Plot" button on pop-up properties. Defaults to False.
  • has_action(bool): Enable "Action" button on pop-up properties. Defaults to False.
  • extent(list): Extent for the layer (optional)
  • popup_title(str): Title to display on feature popups. Defaults to layer title.
  • excluded_properties(list): List of properties to exclude from feature popups.
  • show_download(boolean): enable download geojson as shapefile. Default is False.
• Returns:
  • mv_layer(MVLayer): the layer object

build_wms_layer(self, endpoint, layer_name, layer_title, layer_variable, viewparams=None, env=None, visible=True, tiled=True, selectable=False, plottable=False, has_action=False, extent=None, public=True, geometry_attribute='geometry', layer_id='', excluded_properties=None, popup_title=None, color_ramp_division_kwargs=None, times=None)

• Description: Build a WMS MVLayer object with supplied arguments.
• Parameters:
  • endpoint(str): URL to GeoServer WMS interface.
  • layer_name(str): Name of GeoServer layer (e.g.: agwa:3a84ff62-aaaa-bbbb-cccc-1a2b3c4d5a6b7c8d-model_boundaries).
  • layer_title(str): Title of MVLayer (e.g.: Model Boundaries).
  • layer_variable(str): Variable type of the layer (e.g.: model_boundaries).
  • layer_id(UUID, int, str): layer_id for non geoserver layer where layer_name may not be unique.
  • viewparams(str): VIEWPARAMS string.
  • env(str): ENV string.
  • visible(bool): Layer is visible when True. Defaults to True.
  • public(bool): Layer is publicly accessible when app is running in Open Portal Mode if True. Defaults to True.
  • tiled(bool): Configure as tiled layer if True. Defaults to True.
  • selectable(bool): Enable feature selection. Defaults to False.
  • plottable(bool): Enable "Plot" button on pop-up properties. Defaults to False.
  • has_action(bool): Enable "Action" button on pop-up properties. Defaults to False.
  • extent(list): Extent for the layer (optional)
  • popup_title(str): Title to display on feature popups. Defaults to layer title.
  • excluded_properties(list): List of properties to exclude from feature popups.
  • geometry_attribute(str): Name of the geometry attribute. Defaults to "geometry".
  • color_ramp_division_kwargs(dict): arguments from map_manager.generate_custom_color_ramp_divisions
  • times (list): List of time steps if layer is time-enabled. Times should be represented as strings in ISO 8601 format (e.g.: ["20210322T112511Z", "20210322T122511Z", "20210322T132511Z"]). Currently only supported in CesiumMapView.
• Returns:
  • mv_layer(MVLayer): the layer object

build_arc_gis_layer(self, endpoint, layer_name, layer_title, layer_variable, viewparams=None, env=None, visible=True, tiled=True, selectable=False, plottable=False, has_action=False, extent=None, public=True, geometry_attribute='geometry', layer_id='', excluded_properties=None, popup_title=None)

• Description: Build an AcrGIS Map Server MVLayer object with supplied arguments
• Parameters:
  • endpoint(str): URL to GeoServer WMS interface.
  • layer_name(str): Name of GeoServer layer (e.g.: agwa:3a84ff62-aaaa-bbbb-cccc-1a2b3c4d5a6b7c8d-model_boundaries).
  • layer_title(str): Title of MVLayer (e.g.: Model Boundaries).
  • layer_variable(str): Variable type of the layer (e.g.: model_boundaries).
  • layer_id(UUID, int, str): layer_id for non geoserver layer where layer_name may not be unique.
  • viewparams(str): VIEWPARAMS string.
  • env(str): ENV string.
  • visible(bool): Layer is visible when True. Defaults to True.
  • public(bool): Layer is publicly accessible when app is running in Open Portal Mode if True. Defaults to True.
  • tiled(bool): Configure as tiled layer if True. Defaults to True.
  • selectable(bool): Enable feature selection. Defaults to False.
  • plottable(bool): Enable "Plot" button on pop-up properties. Defaults to False.
  • has_action(bool): Enable "Action" button on pop-up properties. Defaults to False.
  • extent(list): Extent for the layer (optional)
  • popup_title(str): Title to display on feature popups. Defaults to layer title.
  • excluded_properties(list): List of properties to exclude from feature popups.
  • geometry_attribute(str): Name of the geometry attribute. Defaults to "geometry".
• Returns:
  • mv_layer(MVLayer): the layer object

_build_mv_layer(self, layer_source, layer_name, layer_title, layer_variable, options, layer_id=None, extent=None, visible=True, public=True, selectable=False, plottable=False, has_action=False, excluded_properties=None, popup_title=None, geometry_attribute=None, style_map=None, show_download=False, times=None,label_options=None)

• Description: Build an MVLayer object with supplied arguments.
• Parameters:
  • layer_source(str): OpenLayers Source to use for the MVLayer (e.g.: "TileWMS", "ImageWMS", "GeoJSON").
  • layer_name(str): Name of GeoServer layer (e.g.: agwa:3a84ff62-aaaa-bbbb-cccc-1a2b3c4d5a6b7c8d-model_boundaries).
  • layer_title(str): Title of MVLayer (e.g.: Model Boundaries).
  • layer_variable(str): Variable type of the layer (e.g.: model_boundaries).
  • layer_id(UUID, int, str): layer_id for non geoserver layer where layer_name may not be unique.
  • visible(bool): Layer is visible when True. Defaults to True.
  • selectable(bool): Enable feature selection. Defaults to False.
  • plottable(bool): Enable "Plot" button on pop-up properties. Defaults to False.
  • has_action(bool): Enable "Action" button on pop-up properties. Defaults to False.
  • extent(list): Extent for the layer (optional)
  • popup_title(str): Title to display on feature popups. Defaults to layer title.
  • excluded_properties(list): List of properties to exclude from feature popups.
  • geometry_attribute(str): Name of the geometry attribute (optional)
  • style_map(dict): Style map dictionary. See MVLayer documentation for examples of style maps (optional)
  • show_download(boolean): enable download layer. (only works for geojson layer).
  • times (list): List of time steps if layer is time-enabled. Times should be represented as strings in ISO 8601 format (e.g.: ["20210322T112511Z", "20210322T122511Z", "20210322T132511Z"]). Currently only supported in CesiumMapView.
  • label_options(dict): Dictionary for labeling. Possibilities include label_property (the name of the property to label), font (label font), text_align (alignment of the label), offset_x (x offset) (optional)
• Returns:
  • mv_layer(MVLayer): the MVLayer object

build_layer_group(self, id, display_name, layers, layer_control='checkbox', visible=True, public=True)

• Description: Build a layer group object
• Parameters:
  • id(str): Unique identifier for the layer group.
  • display_name(str): Name displayed in MapView layer selector/legend.
  • layers(list(MVLayer)): List of layers to include in the layer group.
  • layer_control(str): Type of control for layers. Either 'checkbox' or 'radio'. Defaults to checkbox.
  • visible(bool): Whether layer group is initially visible. Defaults to True.
  • public(bool): enable public to see this layer group if True.
• Returns:
  • layer_group(dict): layer group definition

get_vector_style_map(self)

• Description: Builds the style map for vector layers. Override this to change the styles of features on the map.
• Returns:
  • style_map(dict): the style map
• Example:

      point_fill_color = 'darkgreen'
      point_outline_color = 'green'
      
      line_color = 'yellow'
  
      polygon_outline_color = 'orange'
      polygon_fill_color = 'red'
      style_map = {
          'Point': {'ol.style.Style': {
              'image': {'ol.style.Circle': {
                  'radius': 5,
                  'fill': {'ol.style.Fill': {
                      'color': color,
                  }},
                  'stroke': {'ol.style.Stroke': {
                      'color': color,
                  }}
              }}
          }},
          'LineString': {'ol.style.Style': {
              'stroke': {'ol.style.Stroke': {
                  'color': color,
                  'width': 2
              }}
          }},
          'Polygon': {'ol.style.Style': {
              'stroke': {'ol.style.Stroke': {
                  'color': color,
                  'width': 2
              }},
              'fill': {'ol.style.Fill': {
                  'color': 'rgba(255, 215, 0, 0.1)'
              }}
          }},
      }
  
      return style_map   

get_wms_endpoint(self)

• Description: Get the public WMS endpoint for GeoServer
• Returns:
  • endpoint(str): the public WMS endpoint

get_map_extent(self)

• Description: Get the default view and extent for the project.
• Returns:
  • mv_view(MVView): the default view
  • extent(list): the extent of the project

build_legend(self, layer, units="")

• Description: Build Legend data for a given layer
• Parameters:
  • layer: result.layer object
  • units: unit for the legend.
• Returns: legend_info(dict): Legend data associated with the layer

generate_custom_color_ramp_division(self, min_value, max_value, num_divisions=10, value_precision=2, first_division=1, top_offset=0, bottom_offset=0, color_ramp="", color_prefix='color', no_data_value=None)

• Description: Generate custom elevation divisions.
• Parameters:
  • min_value(number): minimum value.
  • max_value(number): maximum value.
  • num_divisison(int): number of divisions.
  • value_precision(int): level of precision for legend values.
  • first_division(int): first division number (defaults to 1).
  • top_offset(number): offset from top of color ramp (defaults to 0).
  • bottom_offset(number): offset from bottom of color ramp (defaults to 0).
  • prefix(str): name of division variable prefix (i.e.: 'val' for pattern 'val1').
  • color_ramp(str): color ramp name in COLOR_RAMPS dict. Options are ['Blue', 'Blue and Red', 'Flower Field', 'Galaxy Berries', 'Heat Map', 'Olive Harmony', 'Mother Earth', 'Rainforest Frogs', 'Retro FLow', 'Sunset Fade']
  • color_prefix(str): name of color variable prefix (i.e.: 'color' for pattern 'color1').
  • no_data_value (str): set no data value for the color ramp. (defaults to None).
• Returns:
  • divisions(dict(name, value)): custom divisions

get_plot_for_layer_feature(self, layer_name, feature_id)

• Description: Get plot data for given feature on given layer. Override this for your specific application's features' data.
• Parameters:
  • layer_name(str): Name/id of layer.
  • feature_id(str): PostGIS Feature ID of feature.
• Returns:
  • plot_title(str): title to appear on plot
  • plot_data(list(dict)): plot data
  • layout(dict): layout options

Spatial Manager

Spatial Managers help us work with geoserver and manage certain configurations for our map managers to use.

You'll need to use the BaseSpatialManager class to build your own SpatialManager class to use in your workflows application.

from tethysext.workflows.services.base_spatial_manager import BaseSpatialManager

There are some methods you'll need to override in order to use, along with some that are built in and can be used out the gate. Feel free to override any of these methods to fit your application's needs.

Built-in Methods

__init__(self, geoserver_engine)

• Description: Initializer used for the Spatial Manager class.
• Parameters:
  • geoserver_engine(tethys_dataset_services.GeoServerEngine): Tethys GeoServer engine

create_workspace(self)

• Description: Creates a workspace in GeoServer

get_ows_endpoint(self, public_endpoint=True)

• Description: Returns the GeoServer endpoint for OWS services (with trailing slash).
• Parameters:
  • public_endpoint(bool): return with the public endpoint if True.

get_wms_endpoint(self, public=True)

• Description: Returns the GeoServer endpoint for WMS services (with trailing slash).
• Parameters:
  • public(bool): return with the public endpoint if True.

reload(self, ports=None, public_endpoint=True)

• Description: Reload the in memory catalog of each member of the geoserver cluster.
• Parameters:
  • ports(list): list of ports for GeoServer to use
  • public_endpoint(bool): use the public geoserver endpoint if True, otherwise use the internal endpoint

Methods to Override

get_extent_for_project(self, *args, **kwargs)

• Description: Get extent of the project. This method needs to be overrided and to return a set of four coordinates with the lowest x and y values first, followed by the highest x and y values in this format: [min_x, min_y, max_x, max_y]
• Example:

  def get_extent_for_project(self, project=None):
      default_extent = [-124.67, 25.84, -66.95, 49.38]  # Default for continental USA
      if project is None:
          return default_extent
  
      project_extent = project.get_attribute('project_extent')
      if project_extent is None:
          corners = [(default_extent[0], default_extent[1]), (default_extent[2], default_extent[3])]
      else:
          corners = [(project_extent[0], project_extent[1]), (project_extent[2], project_extent[3])]
      # get min_x, min_y, max_x, max_y from corners
      min_x = min([corner[0] for corner in corners])
      min_y = min([corner[1] for corner in corners])
      max_x = max([corner[0] for corner in corners])
      max_y = max([corner[1] for corner in corners])
  
      return [min_x, min_y, max_x, max_y]

get_projection_units(self, *args, **kwargs)

• Description: Get units of the given projection
• Example:

  from tethysext.atcore.services.exceptions import UnitsNotFound, UnknownUnits
  ...
  def get_projection_units(self, model_db, srid):
      if srid not in self._projection_units:
          db_engine = model_db.get_engine()
          try:
              sql = "SELECT srid, proj4text FROM spatial_ref_sys WHERE srid = {}".format(srid)
              ret = db_engine.execute(sql)
  
              # Parse proj4text to get units
              # e.g.: +proj=utm +zone=21 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
              proj4text = ''
              units = ''
  
              for row in ret:
                  proj4text = row.proj4text
          finally:
              db_engine.dispose()
  
          proj4parts = proj4text.split('+')
  
          for part in proj4parts:
              spart = part.strip()
              if 'units' in spart:
                  units = spart.replace('units=', '')
  
          if not units:
              raise UnitsNotFound('Unable to determine units of project with srid: {}'.format(srid))
  
          if 'ft' in units:
              self._projection_units[srid] = self.U_IMPERIAL
          elif 'm' in units:
              self._projection_units[srid] = self.U_METRIC
          else:
              raise UnknownUnits('"{}" is an unrecognized form of units. From srid: {}'.format(units, srid))
  
      return self._projection_units[srid]

get_projection_string(self, *args, **kwargs)

• Description: Get the projection string as either wkt or proj4 format
• Example:

  def get_projection_string(self, model_db, srid, proj_format=''):
      if not proj_format:
          proj_format = self.PRO_WKT
  
      if proj_format not in (self.PRO_WKT, self.PRO_PROJ4):
          raise ValueError('Invalid projection format given: {}. Use either SpatialManager.PRO_WKT or '
                          'SpatialManager.PRO_PROJ4.'.format(proj_format))
  
      if srid not in self._projection_string or proj_format not in self._projection_string[srid]:
          db_engine = model_db.get_engine()
          try:
              if proj_format is self.PRO_WKT:
                  sql = "SELECT srtext AS proj_string FROM spatial_ref_sys WHERE srid = {}".format(srid)
              else:
                  sql = "SELECT proj4text AS proj_string FROM spatial_ref_sys WHERE srid = {}".format(srid)
  
              ret = db_engine.execute(sql)
              projection_string = ''
  
              for row in ret:
                  projection_string = row.proj_string
          finally:
              db_engine.dispose()
  
          if srid not in self._projection_string:
              self._projection_string[srid] = {}
  
          self._projection_string[srid].update({proj_format: projection_string})
  
      return self._projection_string[srid][proj_format]