Projection with Geoviews/HVplot

GeoViews
1

Hallo,

I am trying to use a projection where the entire globe isn’t shown:

nodes = gv.Points(lonlat_df)

trimesh = gv.TriMesh((df, nodes)).redim(
    x="Longitude (˚E)", y="Latitude (˚N)", z="Resolution (m**2)"
)

#projection = ccrs.PlateCarree()
projection = ccrs.NearsidePerspective()

projected_trimesh = gv.project(trimesh, projection=projection)

FESOM_Resolution = rasterize(projected_trimesh).opts(
    cmap="bgy_r",
    projection=projection,
    width=800,
    height=600,
    colorbar=True,
    colorbar_position="bottom",
    tools=["hover"],
    clabel="Resolution as Average Element Edge Length (km)",
    bgcolor="darkgray",
    color_levels=20,
    cformatter="%.0f",
    clim=(20, 180),
    title="FESOM Resolution (MIS 3 Closed: {:,} 2d Nodes)".format(mesh.n2d),

)

FESOM_Resolution

However, this yields an error with index out of bounds:

IndexError: index 99834 is out of bounds for size 41391

Any hints would help!
Thanks,
PG

2

Don’t have any immediate suggestions, what this indicates to me is that the projection operation is dropping a bunch of nodes because they fall outside the projection bounds. This ends up confusing the trimesh code which uses simple indexes to look up the vertex positions. I’d consider this a bug in HoloViews tbh which should be addressable by switching to a pandas merge to look up the positions.

3

Should I open an issue for this? If yes, under which project? I’ll try to include a minimal working example independent of any external data

4

That would be great. HoloViews is likely the best place since that’s where the fix would be.