Map View¶

class tethys_sdk.gizmos.MapView(height='100%', width='100%', basemap='OpenStreetMap', view={'center': [-100, 40], 'zoom': 2}, controls=[], layers=[], draw=None, legend=False, attributes={}, classes='', disable_basemap=False, feature_selection=None)¶

The Map View gizmo can be used to produce interactive maps of spatial data. It is powered by OpenLayers 3, a free and open source pure javascript mapping library. It supports layers in a variety of different formats including WMS, Tiled WMS, GeoJSON, KML, and ArcGIS REST. It includes drawing capabilities and the ability to create a legend for the layers included in the map.

Shapes that are drawn on the map by users can be retrieved from the map via a hidden text field named ‘geometry’ and it is updated every time the map is changed. The text in the text field is a string representation of JSON. The geometry definition contained in this JSON can be formatted as either GeoJSON or Well Known Text. This can be configured via the output_format option of the MVDraw object. If the Map View is embedded in a form, the geometry that is drawn on the map will automatically be submitted with the rest of the form via the hidden text field.

height¶

str

Height of the map element. Any valid css unit of length (e.g.: ‘500px’). Defaults to ‘520px’.

width¶

str

Width of the map element. Any valid css unit of length (e.g.: ‘100%’). Defaults to ‘100%’.

basemap¶

str or dict

The base map to dispaly: either OpenStreetMap, MapQuest, or a Bing map. Valid values for the string option are: ‘OpenStreetMap’ and ‘MapQuest’. If you wish to configure the base map with options, you must use the dictionary form. The dictionary form is required to use a Bing map, because an API key must be passed as an option. See below for more detail.

view¶

MVView

An MVView object specifying the initial view or extent for the map.

controls¶

list

A list of controls to add to the map. The list can be a list of strings or a list of dictionaries. Valid controls are ZoomSlider, Rotate, FullScreen, ScaleLine, ZoomToExtent, and ‘MousePosition’. See below for more detail.

layers¶

list

A list of MVLayer objects.

draw¶

MVDraw

An MVDraw object specifying the drawing options.

disable_basemap¶

bool

Render the map without a base map.

feature_selection¶

bool

A dictionary of global feature selection options. See below.

attributes¶

dict

A dictionary representing additional HTML attributes to add to the primary element (e.g. {“onclick”: “run_me();”}).

classes¶

str

Additional classes to add to the primary HTML element (e.g. “example-class another-class”).

Options Dictionaries

Many of the options above will accept dictionaries with additional options. These dictionaries should be structured with a single key that is the name of the original option with a value of another dictionary containing the additional options. For example, to provide additional options for the ‘ZoomToExtent’ control, you would create a dictionary with key ‘ZoomToExtent’ and value of a dictionary with the additional options like this:

{'ZoomToExtent': {'projection': 'EPSG:4326', 'extent': [-135, 22, -55, 54]}}

Most of the additional options correspond with the options objects in the OpenLayers API. The following sections provide links to the OpenLayers objects that you can refer to when selecting the options.

Base Maps

There are three base maps supported by the Map View gizmo: OpenStreetMap, Bing, and MapQuest. Use the following links to learn about the additional options you can configure the base maps with:

Bing: ol.source.BingMaps
MapQuest: ol.source.MapQuest
OpenStreetMap: ol.source.OSM

{'Bing': {'key': 'Ap|k3yheRE', 'imagerySet': 'Aerial'}}

Controls

Use the following links to learn about options for the different controls:

Feature Selection

The feature_selection dictionary contains global settings that can be used to modify the behavior of the feature selection functionality. An explanation of valid options follows:

multiselect: Set to True to allow multiple features to be selected while holding the shift key on the keyboard. Defaults to False.
sensitivity: Integer value that adjust the feature selection sensitivity. Defaults to 2.

Example

# CONTROLLER
from tethys_sdk.gizmos import MapView, MVDraw, MVView, MVLayer, MVLegendClass

# Define view options
view_options = MVView(
    projection='EPSG:4326',
    center=[-100, 40],
    zoom=3.5,
    maxZoom=18,
    minZoom=2
)

# Define drawing options
drawing_options = MVDraw(
    controls=['Modify', 'Delete', 'Move', 'Point', 'LineString', 'Polygon', 'Box'],
    initial='Point',
    output_format='WKT'
)

# Define GeoJSON layer
geojson_object = {
  'type': 'FeatureCollection',
  'crs': {
    'type': 'name',
    'properties': {
      'name': 'EPSG:3857'
    }
  },
  'features': [
    {
      'type': 'Feature',
      'geometry': {
        'type': 'Point',
        'coordinates': [0, 0]
      }
    },
    {
      'type': 'Feature',
      'geometry': {
        'type': 'LineString',
        'coordinates': [[4e6, -2e6], [8e6, 2e6]]
      }
    },
    {
      'type': 'Feature',
      'geometry': {
        'type': 'Polygon',
        'coordinates': [[[-5e6, -1e6], [-4e6, 1e6], [-3e6, -1e6]]]
      }
    }
  ]
}

geojson_layer = MVLayer(source='GeoJSON',
                        options=geojson_object,
                        legend_title='Test GeoJSON',
                        legend_extent=[-46.7, -48.5, 74, 59],
                        legend_classes=[
                            MVLegendClass('polygon', 'Polygons', fill='rgba(255,255,255,0.8)', stroke='#3d9dcd'),
                            MVLegendClass('line', 'Lines', stroke='#3d9dcd')
                        ])

# Define GeoServer Layer
geoserver_layer = MVLayer(source='ImageWMS',
                          options={'url': 'http://192.168.59.103:8181/geoserver/wms',
                                   'params': {'LAYERS': 'topp:states'},
                                   'serverType': 'geoserver'},
                          legend_title='USA Population',
                          legend_extent=[-126, 24.5, -66.2, 49],
                          legend_classes=[
                              MVLegendClass('polygon', 'Low Density', fill='#00ff00', stroke='#000000'),
                              MVLegendClass('polygon', 'Medium Density', fill='#ff0000', stroke='#000000'),
                              MVLegendClass('polygon', 'High Density', fill='#0000ff', stroke='#000000')
                          ])

# Define KML Layer
kml_layer = MVLayer(source='KML',
                    options={'url': '/static/tethys_gizmos/data/model.kml'},
                    legend_title='Park City Watershed',
                    legend_extent=[-111.60, 40.57, -111.43, 40.70],
                    legend_classes=[
                        MVLegendClass('polygon', 'Watershed Boundary', fill='#ff8000'),
                        MVLegendClass('line', 'Stream Network', stroke='#0000ff'),
                    ])

# Tiled ArcGIS REST Layer
arc_gis_layer = MVLayer(source='TileArcGISRest',
                        options={'url': 'http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/' + 'Specialty/ESRI_StateCityHighway_USA/MapServer'},
                        legend_title='ESRI USA Highway',
                        legend_extent=[-173, 17, -65, 72])

# Define map view options
map_view_options = MapView(
        height='600px',
        width='100%',
        controls=['ZoomSlider', 'Rotate', 'FullScreen',
                  {'MousePosition': {'projection': 'EPSG:4326'}},
                  {'ZoomToExtent': {'projection': 'EPSG:4326', 'extent': [-130, 22, -65, 54]}}],
        layers=[geojson_layer, geoserver_layer, kml_layer, arc_gis_layer],
        view=view_options,
        basemap='OpenStreetMap',
        draw=drawing_options,
        legend=True
)

# TEMPLATE

{% gizmo map_view map_view_options %}

MVLayer¶

class tethys_sdk.gizmos.MVLayer(source, options, legend_title, layer_options=None, legend_classes=None, legend_extent=None, legend_extent_projection='EPSG:4326', feature_selection=False, geometry_attribute=None)¶

MVLayer objects are used to define map layers for the Map View Gizmo.

source¶

str, required

The source or data type of the layer (e.g.: ImageWMS)

options¶

dict, required

A dictionary representation of the OpenLayers options object for ol.source.

legend_title¶

str, required

The human readable name of the layer that will be displayed in the legend.

layer_options¶

dict

A dictionary representation of the OpenLayers options object for ol.layer.

feature_selection¶

bool

Set to True to enable feature selection on this layer. Defaults to False.

geometry_attribute¶

str

The name of the attribute in the shapefile that describes the geometry

legend_classes¶

list

A list of MVLegendClass objects.

legend_extent¶

list

A list of four ordinates representing the extent that will be used on “zoom to layer”: [minx, miny, maxx, maxy].

legend_extent_projection¶

str

The EPSG projection of the extent coordinates. Defaults to “EPSG:4326”.

Example

# Define GeoJSON layer
geojson_object = {
  'type': 'FeatureCollection',
  'crs': {
    'type': 'name',
    'properties': {
      'name': 'EPSG:3857'
    }
  },
  'features': [
    {
      'type': 'Feature',
      'geometry': {
        'type': 'Point',
        'coordinates': [0, 0]
      }
    },
    {
      'type': 'Feature',
      'geometry': {
        'type': 'LineString',
        'coordinates': [[4e6, -2e6], [8e6, 2e6]]
      }
    },
    {
      'type': 'Feature',
      'geometry': {
        'type': 'Polygon',
        'coordinates': [[[-5e6, -1e6], [-4e6, 1e6], [-3e6, -1e6]]]
      }
    }
  ]
}

geojson_layer = MVLayer(source='GeoJSON',
                        options=geojson_object,
                        legend_title='Test GeoJSON',
                        legend_extent=[-46.7, -48.5, 74, 59],
                        legend_classes=[
                            MVLegendClass('polygon', 'Polygons', fill='rgba(255,255,255,0.8)', stroke='#3d9dcd'),
                            MVLegendClass('line', 'Lines', stroke='#3d9dcd')
                        ])

# Define GeoServer Layer
geoserver_layer = MVLayer(source='ImageWMS',
                          options={'url': 'http://192.168.59.103:8181/geoserver/wms',
                                   'params': {'LAYERS': 'topp:states'},
                                   'serverType': 'geoserver'},
                          legend_title='USA Population',
                          legend_extent=[-126, 24.5, -66.2, 49],
                          legend_classes=[
                              MVLegendClass('polygon', 'Low Density', fill='#00ff00', stroke='#000000'),
                              MVLegendClass('polygon', 'Medium Density', fill='#ff0000', stroke='#000000'),
                              MVLegendClass('polygon', 'High Density', fill='#0000ff', stroke='#000000')
                          ])

# Define GeoServer Tile Layer with Custom tile grid
# The default EPSG:900913 gridset can be used with OpenLayers.
# You must ensure that OpenLayers requests tiles with the same gridset and origin as the gridset GeoServer uses
# to use GeoWebCaching capabilities. This is done by setting the TILESORIGIN parameter and specifying a custom tileGrid.
# Refer to OpenLayers API for ol.tilegrid.TileGrid for explanation and options.
# See: http://docs.geoserver.org/2.7.0/user/webadmin/tilecache/index.html
geoserver_layer = MVLayer(source='TileWMS',
                          options={'url': 'http://192.168.59.103:8181/geoserver/wms',
                                   'params': {'LAYERS': 'topp:states',
                                              'TILED': True,
                                              'TILESORIGIN': '0.0,0.0'},
                                   'serverType': 'geoserver',
                                   'tileGrid': {
                                   'resolutions': [
                                       156543.03390625,
                                       78271.516953125,
                                       39135.7584765625,
                                       19567.87923828125,
                                       9783.939619140625,
                                       4891.9698095703125,
                                       2445.9849047851562,
                                       1222.9924523925781,
                                       611.4962261962891,
                                       305.74811309814453,
                                       152.87405654907226,
                                       76.43702827453613,
                                       38.218514137268066,
                                       19.109257068634033,
                                       9.554628534317017,
                                       4.777314267158508,
                                       2.388657133579254,
                                       1.194328566789627,
                                       0.5971642833948135,
                                       0.2985821416974068,
                                       0.1492910708487034,
                                       0.0746455354243517,
                                     ],
                                     'extent': [-20037508.34, -20037508.34, 20037508.34, 20037508.34],
                                     'origin': [0, 0],
                                     'tileSize': [256, 256]
                                   }
                          },
                          legend_title='USA Population')

# Define KML Layer
kml_layer = MVLayer(source='KML',
                    options={'url': '/static/tethys_gizmos/data/model.kml'},
                    legend_title='Park City Watershed',
                    legend_extent=[-111.60, 40.57, -111.43, 40.70],
                    legend_classes=[
                        MVLegendClass('polygon', 'Watershed Boundary', fill='#ff8000'),
                        MVLegendClass('line', 'Stream Network', stroke='#0000ff'),
                    ])

# Tiled ArcGIS REST Layer
arc_gis_layer = MVLayer(source='TileArcGISRest',
                        options={'url': 'http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/' + 'Specialty/ESRI_StateCityHighway_USA/MapServer'},
                        legend_title='ESRI USA Highway',
                        legend_extent=[-173, 17, -65, 72]),

MVLegendClass¶

class tethys_sdk.gizmos.MVLegendClass(type, value, fill='', stroke='', ramp=[])¶

MVLegendClasses are used to define the classes listed in the legend.

type¶

str, required

The type of feature to be represented by the legend class. Either ‘point’, ‘line’, ‘polygon’, or ‘raster’.

value¶

str, required

The value or name of the legend class.

fill¶

str

Valid RGB color for the fill (e.g.: ‘#00ff00’, ‘rgba(0, 255, 0, 0.5)’). Required for ‘point’ or ‘polygon’ types.

stoke¶

str

Valid RGB color for the stoke/line (e.g.: ‘#00ff00’, ‘rgba(0, 255, 0, 0.5)’). Required for ‘line’ types and optional for ‘polygon’ types.

ramp¶

list

A list of hexidecimal RGB colors that will be used to construct a color ramp. Required for ‘raster’ types.

Example

point_class = MVLegendClass(type='point', value='Cities', fill='#00ff00')
line_class = MVLegendClass(type='line', value='Roads', stroke='rbga(0,0,0,0.7)')
polygon_class = MVLegendClass(type='polygon', value='Lakes', stroke='#0000aa', fill='#0000ff')

MVLegendImageClass¶

class tethys_sdk.gizmos.MVLegendImageClass(value, image_url)¶

MVLegendImageClasses are used to define the classes listed in the legend using a pre-generated image.

value¶

str, required

The value or name of the legend class.

image_url¶

str, required

The url to the legend image.

Example

image_class = MVLegendImageClass(value='Cities',
                                 image_url='https://upload.wikimedia.org/wikipedia/commons/d/da/The_City_London.jpg'
                                 )

MVLegendGeoServerImageClass¶

class tethys_sdk.gizmos.MVLegendGeoServerImageClass(value, geoserver_url, style, layer, width=20, height=10)¶

MVLegendGeoServerImageClasses are used to define the classes listed in the legend using the GeoServer generated legend.

value¶

str, required

The value or name of the legend class.

geoserver_url¶

str, required

The url to your geoserver (e.g. http://localhost:8181/geoserver).

style¶

str, required

The name of the geoserver style (e.g. green).

layer¶

str, required

The name of the geoserver layer (e.g. rivers).

width¶

int

The legend width (default is 20).

height¶

int

The legend height (default is 10).

Example

image_class = MVLegendGeoServerImageClass(value='Cities',
                                          geoserver_url='http://localhost:8181/geoserver',
                                          style='green',
                                          layer='rivers',
                                          width=20,
                                          height=10)

MVDraw¶

class tethys_sdk.gizmos.MVDraw(controls, initial, output_format='GeoJSON')¶

MVDraw objects are used to define the drawing options for Map View.

controls¶

list, required

List of drawing controls to add to the map. Valid options are ‘Modify’, ‘Delete’, ‘Move’, ‘Point’, ‘LineString’, ‘Polygon’ and ‘Box’.

initial¶

str, required

Drawing control to be enabled initially. Must be included in the controls list.

output_format¶

str

Format to output to the hidden text area. Either ‘WKT’ (for Well Known Text format) or ‘GeoJSON’. Defaults to ‘GeoJSON’

Example

drawing_options = MVDraw(
    controls=['Modify', 'Delete', 'Move', 'Point', 'LineString', 'Polygon', 'Box'],
    initial='Point',
    output_format='WKT'
)

MVView¶

class tethys_sdk.gizmos.MVView(projection, center, zoom, maxZoom=28, minZoom=0)¶

MVView objects are used to define the initial view of the Map View. The initial view is set by specifying a center and a zoom level.

projection¶

str

Projection of the center coordinates given. This projection will be used to transform the coordinates into the default map projection (EPSG:3857).

center¶

list

An array with the coordinates of the center point of the initial view.

zoom¶

int or float

The zoom level for the initial view.

maxZoom¶

int or float

The maximum zoom level allowed. Defaults to 28.

minZoom¶

int or float

The minimum zoom level allowed. Defaults to 0.

Example

view_options = MVView(
    projection='EPSG:4326',
    center=[-100, 40],
    zoom=3.5,
    maxZoom=18,
    minZoom=2
)

JavaScript API¶

For advanced features, the JavaScript API can be used to interact with the OpenLayers map object that is generated by the Map View JavaScript library.

TETHYS_MAP_VIEW.getMap()¶

This method returns the OpenLayers map object. You can use the OpenLayers Map API version 3.10.1 to perform operations on this object such as adding layers and custom controls.

$(function() { //wait for page to load

    var ol_map = TETHYS_MAP_VIEW.getMap();
    ol_map.addLayer(...);
    ol_map.setView(...);

});

Caution

The Map View Gizmo is powered by OpenLayers version 3.10.1. When referring to the OpenLayers documentation, ensure that you are browsing the correct version of documentation (see the URL of the documentation page).

TETHYS_MAP_VIEW.updateLegend()¶

This method can be used to update the legend after removing/adding layers to the map.

$(function() { //wait for page to load

    var ol_map = TETHYS_MAP_VIEW.getMap();
    ol_map.addLayer(...);
    TETHYS_MAP_VIEW.updateLegend();

});

TETHYS_MAP_VIEW.zoomToExtent(latlongextent)¶

This method can be used to set the view of the map to the extent provided. The extent is assumed to be given in the EPSG:4326 coordinate reference system.

$(function() { //wait for page to load

    var extent = [-109.49945001309617, 37.58047995600726, -109.44540360290348, 37.679502621605735];
    TETHYS_MAP_VIEW.zoomToExtent(extent);
});

TETHYS_MAP_VIEW.clearSelection()¶

This method applies to the WMS layer feature selection functionality. Use this method to clear the current selection via JavaScript.

TETHYS_MAP_VIEW.clearSelection();

TETHYS_MAP_VIEW.overrideSelectionStyler(geometry_type, styler)¶

This method applies to the WMS layer feature selection functionality. This method can be used to override the default styling for the points, lines, and polygons selected feature layers.

geometry_type (str): The type of the layer that the styler function will apply to. One of: ‘points’, ‘lines’, or ‘polygons’.
styler (func): A function that accepts two arguments, feature and resolution, and returns an array of valid ol.style objects.

function my_styler(feature, resolution) {
var image, properties;
    properties = feature.getProperties();

    // Default icon
    image = new ol.style.Circle({
        radius: 5,
        fill: new ol.style.Fill({
            color: 'red'
        })
    });

    if ('type' in properties) {
        if (properties.type === 'TANK') {
            image = new ol.style.RegularShape({
                fill: new ol.style.Fill({
                    color: SELECTED_NODE_COLOR
                }),
                stroke: new ol.style.Stroke({
                    color: 'white',
                    width: 1
                }),
                points: 4,
                radius: 14,
                rotation: 0,
                angle: Math.PI / 4
            });

        }
        else if (properties.type === 'RESERVOIR') {
            image = new ol.style.RegularShape({
                fill: new ol.style.Fill({
                    color: SELECTED_NODE_COLOR
                }),
                stroke: new ol.style.Stroke({
                    color: 'white',
                    width: 1
                }),
                points: 3,
                radius: 14,
                rotation: 0,
                angle: 0
            });
        }
    }

    return [new ol.style.Style({image: image})];

}

TETHYS_MAP_VIEW.overrideSelectionStyler('points', my_styler);

TETHYS_MAP_VIEW.onSelectionChange(callback)¶

This method applies to the WMS layer feature selection functionality. The callback function provided will be called each time the feature selection is changed.

callback (func): A function that accepts three arguments, points_layer, lines_layer, polygons_layer. These are handles on the OpenLayers layers that are rendering the selected features. The features are divided into three layers by type.

function my_callback(points_layer, lines_layer, polygons_layer) {
   console.log(points_layer);
}

TETHYS_MAP_VIEW.onSelectionChange(my_callback);

TETHYS_MAP_VIEW.getSelectInteraction()¶

This method applies to the WFS/GeoJSON/KML layer feature selection functionality.

$(function() { //wait for page to load

    var selection_interaction = TETHYS_MAP_VIEW.getSelectInteraction();

    //when selected, print feature to developers console
    selection_interaction.getFeatures().on('change:length', function(e) {
      if (e.target.getArray().length > 0) {
        // this means there is at least 1 feature selected
        var selected_feature = e.target.item(0); // 1st feature in Collection
        console.log(selected_feature);

      }
    });

});

TETHYS_MAP_VIEW.reInitializeMap()¶

This method is intended for initializing a map generated from an AJAX request.

Caution

This method assumes there is only one and that there will only ever be one map on the page.

Note

In order to use this, you will either need to use a MapView gizmo or import the JavaScript/CSS libraries in the main html template page.

For example:

{% block styles %}
  {{ block.super }}
  <link rel="stylesheet" href="/static/tethys_gizmos/vendor/openlayers/ol.css"" type="text/css">
{% endblock %}

{% block global_scripts %}
  {{ block.super }}
  <script src="/static/tethys_gizmos/vendor/openlayers/ol.js" type="text/javascript"></script>
{% endblock %}

...

{% block scripts %}
  {{ block.super }}
  <script src="/static/tethys_gizmos/js/tethys_map_view.js" type="text/javascript"></script>
{% endblock %}

Four elements are required:

1) A controller for the AJAX call with a map view gizmo.

@login_required()
def dam_break_map_ajax(request):
    """
    Controller for the dam_break_map ajax request.
    """
    if request.GET:
        ...

        #get layers
        map_layer_list = ...

        # Define initial view for Map View
        view_options = MVView(
            projection='EPSG:4326',
            center=[(bbox[0]+bbox[2])/2.0, (bbox[1]+bbox[3])/2.0],
            zoom=10,
            maxZoom=18,
            minZoom=2,
        )

        # Configure the map
        map_options = MapView(height='500px',
                              width='100%',
                              layers=map_layer_list,
                              controls=['FullScreen'],
                              view=view_options,
                              basemap='OpenStreetMap',
                              legend=True,
                              )

        context = { 'map_options': map_options }

        return render(request, 'dam_break_map_ajax/map_ajax.html', context)

2) A url map to the controller in app.py

...
    UrlMap(name='dam_break_map_ajax',
           url='dam-break/map/dam_break_map_ajax',
           controller='dam_break.controllers.dam_break_map_ajax'),
...

3) A template for with the tethys gizmo (e.g. map_ajax.html)

{% load tethys_gizmos %}

{% gizmo map_view map_options %}

4) The AJAX call in the javascript

$(function() { //wait for page to load

    $.ajax({
        url: ajax_url,
        method: 'GET',
        data: ajax_data,
        success: function(data) {
            //add new map to map div
            $('#main_map_div').html(data);

            TETHYS_MAP_VIEW.reInitializeMap();
        }
    });

});