Holoviews combined with geoviews.tile_sources causes axis scale error












0















I'm trying to combine a geoviews.tile_sources layer with a datashade layer. Both layers individually result in the correct axis (see image), but when combined (using *) the scale becomes distorted.



import numpy as np
import pandas as pd
import holoviews as hv
from geoviews.tile_sources import EsriImagery
from holoviews.operation.datashader import datashade

hv.extension('bokeh')

lats = np.random.uniform(51.111, 51.222, 10000)
longs = np.random.uniform(1.31, 1.33, 10000)

df = pd.DataFrame({"latitude": lats, "longitude": longs})

points = hv.Points(df, ['longitude', 'latitude'])
shader = datashade(points)

EsriImagery * shader


Incorrect axis



However, both of the individual plots are correct:



shader + EsriImagery


enter image description here










share|improve this question



























    0















    I'm trying to combine a geoviews.tile_sources layer with a datashade layer. Both layers individually result in the correct axis (see image), but when combined (using *) the scale becomes distorted.



    import numpy as np
    import pandas as pd
    import holoviews as hv
    from geoviews.tile_sources import EsriImagery
    from holoviews.operation.datashader import datashade

    hv.extension('bokeh')

    lats = np.random.uniform(51.111, 51.222, 10000)
    longs = np.random.uniform(1.31, 1.33, 10000)

    df = pd.DataFrame({"latitude": lats, "longitude": longs})

    points = hv.Points(df, ['longitude', 'latitude'])
    shader = datashade(points)

    EsriImagery * shader


    Incorrect axis



    However, both of the individual plots are correct:



    shader + EsriImagery


    enter image description here










    share|improve this question

























      0












      0








      0








      I'm trying to combine a geoviews.tile_sources layer with a datashade layer. Both layers individually result in the correct axis (see image), but when combined (using *) the scale becomes distorted.



      import numpy as np
      import pandas as pd
      import holoviews as hv
      from geoviews.tile_sources import EsriImagery
      from holoviews.operation.datashader import datashade

      hv.extension('bokeh')

      lats = np.random.uniform(51.111, 51.222, 10000)
      longs = np.random.uniform(1.31, 1.33, 10000)

      df = pd.DataFrame({"latitude": lats, "longitude": longs})

      points = hv.Points(df, ['longitude', 'latitude'])
      shader = datashade(points)

      EsriImagery * shader


      Incorrect axis



      However, both of the individual plots are correct:



      shader + EsriImagery


      enter image description here










      share|improve this question














      I'm trying to combine a geoviews.tile_sources layer with a datashade layer. Both layers individually result in the correct axis (see image), but when combined (using *) the scale becomes distorted.



      import numpy as np
      import pandas as pd
      import holoviews as hv
      from geoviews.tile_sources import EsriImagery
      from holoviews.operation.datashader import datashade

      hv.extension('bokeh')

      lats = np.random.uniform(51.111, 51.222, 10000)
      longs = np.random.uniform(1.31, 1.33, 10000)

      df = pd.DataFrame({"latitude": lats, "longitude": longs})

      points = hv.Points(df, ['longitude', 'latitude'])
      shader = datashade(points)

      EsriImagery * shader


      Incorrect axis



      However, both of the individual plots are correct:



      shader + EsriImagery


      enter image description here







      python bokeh holoviews datashader geoviews






      share|improve this question













      share|improve this question











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      asked Nov 15 '18 at 18:38









      wabwab

      340212




      340212
























          2 Answers
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          HoloViews elements do no know anything about the coordinate system of your data, while tile sources are defined in a Mercator coordinate system. Therefore when you overlay hv.Points on top of a tile source it assumes your coordinates are already in Mercator coordinates. In order to overlay data situated in different coordinates systems you should therefore use the GeoViews elements, e.g. in your case gv.Points, as described in this user guide. This will ensure that your points are interpreted correctly as lat/lon pairs and can be automatically projected into the same coordinate system as the tile source.






          share|improve this answer































            1














            You're trying to combine a HoloViews object in PlateCarree coordinates with a GeoViews object in Web Mercator coordinates, which differ by a factor of a few million. You can fix it by changing hv.Points() to gv.Points(), which will be a GeoViews object in PlateCaree coordinates that GeoViews will project into the same coordinate system as the tile layer when it's displayed. You can also consider using gv.project_points() to do the projection a single time at the start, rather than the default of re-projecting it each time it's displayed.






            share|improve this answer
























            • D'oh! Philipp answered before I hit post...

              – James A. Bednar
              Nov 15 '18 at 19:13











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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            HoloViews elements do no know anything about the coordinate system of your data, while tile sources are defined in a Mercator coordinate system. Therefore when you overlay hv.Points on top of a tile source it assumes your coordinates are already in Mercator coordinates. In order to overlay data situated in different coordinates systems you should therefore use the GeoViews elements, e.g. in your case gv.Points, as described in this user guide. This will ensure that your points are interpreted correctly as lat/lon pairs and can be automatically projected into the same coordinate system as the tile source.






            share|improve this answer




























              2














              HoloViews elements do no know anything about the coordinate system of your data, while tile sources are defined in a Mercator coordinate system. Therefore when you overlay hv.Points on top of a tile source it assumes your coordinates are already in Mercator coordinates. In order to overlay data situated in different coordinates systems you should therefore use the GeoViews elements, e.g. in your case gv.Points, as described in this user guide. This will ensure that your points are interpreted correctly as lat/lon pairs and can be automatically projected into the same coordinate system as the tile source.






              share|improve this answer


























                2












                2








                2







                HoloViews elements do no know anything about the coordinate system of your data, while tile sources are defined in a Mercator coordinate system. Therefore when you overlay hv.Points on top of a tile source it assumes your coordinates are already in Mercator coordinates. In order to overlay data situated in different coordinates systems you should therefore use the GeoViews elements, e.g. in your case gv.Points, as described in this user guide. This will ensure that your points are interpreted correctly as lat/lon pairs and can be automatically projected into the same coordinate system as the tile source.






                share|improve this answer













                HoloViews elements do no know anything about the coordinate system of your data, while tile sources are defined in a Mercator coordinate system. Therefore when you overlay hv.Points on top of a tile source it assumes your coordinates are already in Mercator coordinates. In order to overlay data situated in different coordinates systems you should therefore use the GeoViews elements, e.g. in your case gv.Points, as described in this user guide. This will ensure that your points are interpreted correctly as lat/lon pairs and can be automatically projected into the same coordinate system as the tile source.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 15 '18 at 19:08









                philippjfrphilippjfr

                1,997611




                1,997611

























                    1














                    You're trying to combine a HoloViews object in PlateCarree coordinates with a GeoViews object in Web Mercator coordinates, which differ by a factor of a few million. You can fix it by changing hv.Points() to gv.Points(), which will be a GeoViews object in PlateCaree coordinates that GeoViews will project into the same coordinate system as the tile layer when it's displayed. You can also consider using gv.project_points() to do the projection a single time at the start, rather than the default of re-projecting it each time it's displayed.






                    share|improve this answer
























                    • D'oh! Philipp answered before I hit post...

                      – James A. Bednar
                      Nov 15 '18 at 19:13
















                    1














                    You're trying to combine a HoloViews object in PlateCarree coordinates with a GeoViews object in Web Mercator coordinates, which differ by a factor of a few million. You can fix it by changing hv.Points() to gv.Points(), which will be a GeoViews object in PlateCaree coordinates that GeoViews will project into the same coordinate system as the tile layer when it's displayed. You can also consider using gv.project_points() to do the projection a single time at the start, rather than the default of re-projecting it each time it's displayed.






                    share|improve this answer
























                    • D'oh! Philipp answered before I hit post...

                      – James A. Bednar
                      Nov 15 '18 at 19:13














                    1












                    1








                    1







                    You're trying to combine a HoloViews object in PlateCarree coordinates with a GeoViews object in Web Mercator coordinates, which differ by a factor of a few million. You can fix it by changing hv.Points() to gv.Points(), which will be a GeoViews object in PlateCaree coordinates that GeoViews will project into the same coordinate system as the tile layer when it's displayed. You can also consider using gv.project_points() to do the projection a single time at the start, rather than the default of re-projecting it each time it's displayed.






                    share|improve this answer













                    You're trying to combine a HoloViews object in PlateCarree coordinates with a GeoViews object in Web Mercator coordinates, which differ by a factor of a few million. You can fix it by changing hv.Points() to gv.Points(), which will be a GeoViews object in PlateCaree coordinates that GeoViews will project into the same coordinate system as the tile layer when it's displayed. You can also consider using gv.project_points() to do the projection a single time at the start, rather than the default of re-projecting it each time it's displayed.







                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Nov 15 '18 at 19:12









                    James A. BednarJames A. Bednar

                    88635




                    88635













                    • D'oh! Philipp answered before I hit post...

                      – James A. Bednar
                      Nov 15 '18 at 19:13



















                    • D'oh! Philipp answered before I hit post...

                      – James A. Bednar
                      Nov 15 '18 at 19:13

















                    D'oh! Philipp answered before I hit post...

                    – James A. Bednar
                    Nov 15 '18 at 19:13





                    D'oh! Philipp answered before I hit post...

                    – James A. Bednar
                    Nov 15 '18 at 19:13


















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