TGMap

A TGMap object manages the display of a map that shows the locations of the barriers in a project. The constructor is passed a reference to Project object that has barrier definitions.

Attributes:
  • map –

    a Bokeh figure object, with x and y ranges defined by the locations of the barriers

  • dots –

    a dictionary that maps region names to a list of circle glyphs for each barrier in a region

  • ranges –

    a data frame that has the range of x and y coordinates for each region
Source code in src/tidegates/widgets.py 
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def __init__(self, bf):
    self.map, self.dots = self._create_map(bf)
    self.ranges = self._create_ranges(bf)

_create_map(bf)

Hidden method, called by the constructor to create a Bokeh figure based on the latitude and longitude of the barriers in a project.

src/tidegates/widgets.py 
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def _create_map(self, bf):
    """
    Hidden method, called by the constructor to create a Bokeh figure 
    based on the latitude and longitude of the barriers in
    a project.
    """
    self.tile_provider = get_provider(xyz.OpenStreetMap.Mapnik)
    p = bk.figure(
        title='Oregon Coast', 
        height=900,
        width=400,
        x_range=(bf.map_info.x.min()*0.997,bf.map_info.x.max()*1.003), 
        y_range=(bf.map_info.y.min()*0.997,bf.map_info.y.max()*1.003),
        x_axis_type='mercator',
        y_axis_type='mercator',
        toolbar_location='below',
        tools=['pan','wheel_zoom','hover','reset'],
        tooltips = [
            ("ID", "@id"),
            ("Region", "@region"),
            ("Type", "@type"),
        ]
    )
    p.add_tile(self.tile_provider)
    p.toolbar.autohide = True
    dots = { }
    for r in bf.regions:
        df = bf.map_info[bf.map_info.region == r]
        c = p.circle('x', 'y', size=5, color='darkslategray', source=df, tags=list(df.id))
        dots[r] = c
        c.visible = False

    self.outer_x = (bf.map_info.x.min()*0.997,bf.map_info.x.max()*1.003)
    self.outer_y = (bf.map_info.y.min()*0.997,bf.map_info.y.max()*1.003)

    return p, dots

_create_ranges(df)

Hidden method, called by the constructor to create a Pandas Dataframe containing the range of latitudes and longitudes of the barriers in a project.

src/tidegates/widgets.py 
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def _create_ranges(self, df):
    """
    Hidden method, called by the constructor to create a Pandas Dataframe 
    containing the range of latitudes and longitudes of the barriers in
    a project.
    """
    g = df.map_info.groupby('region')
    return pd.DataFrame({
        'x_min': g.min().x,
        'x_max': g.max().x,
        'y_min': g.min().y,
        'y_max': g.max().y,
    })

display_regions(selection)

This method is called when the user clicks the checkbox next to the name of a region. Set the visible attribute of each dot to True or False depending on whether the region it is in is selected.

Parameters:
  • selection –

    a list of names of regions currently selected
src/tidegates/widgets.py 
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def display_regions(self, selection):
    """
    This method is called when the user clicks the checkbox next to the name
    of a region.  Set the visible attribute of each dot to True or False depending
    on whether the region it is in is selected.

    Arguments:
      selection:  a list of names of regions currently selected
    """
    for r, dots in self.dots.items():
        dots.visible = r in selection

zoom(selection)

Update the map, setting the x and y range based on the currently selected regions.

Parameters:
  • selection –

    a list of names of regions currently selected
src/tidegates/widgets.py 
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def zoom(self, selection):
    """
    Update the map, setting the x and y range based on the currently selected
    regions.

    Arguments:
      selection:  a list of names of regions currently selected
    """
    if len(selection) > 0:
        xmin = min([self.ranges['x_min'][r] for r in selection])
        xmax = max([self.ranges['x_max'][r] for r in selection])
        ymin = min([self.ranges['y_min'][r] for r in selection])
        ymax = max([self.ranges['y_max'][r] for r in selection])

        mx = (xmax+xmin)/2
        my = (ymax+ymin)/2
        dx = max(5000, xmax - xmin)
        dy = max(5000, ymax - ymin)
        ar = self.map.height / self.map.width

        if dy / dx > ar:
            dx = dy / ar
        else:
            dy = dx * ar

        self.map.x_range.update(start=mx-dx/2-5000, end=mx+dx/2+5000)
        self.map.y_range.update(start=my-dy/2, end=my+dy/2)
    else:
        self.map.x_range.update(start=self.outer_x[0], end=self.outer_x[1])
        self.map.y_range.update(start=self.outer_y[0], end=self.outer_y[1])
    self.map.add_tile(self.tile_provider)