Add a streamplot example on geoaxis

MakieOrg · Jun 8, 2024 · f547b1f · f547b1f
1 parent 26fa3fa
commit f547b1f
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Showing 3 changed files with 51 additions and 2 deletions.
diff --git a/docs/Project.toml b/docs/Project.toml
@@ -28,6 +28,7 @@ GeometryOps = "3251bfac-6a57-4b6d-aa61-ac1fef2975ab"
 GraphMakie = "1ecd5474-83a3-4783-bb4f-06765db800d2"
 ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
 ImageTransformations = "02fcd773-0e25-5acc-982a-7f6622650795"
+Interpolations = "a98d9a8b-a2ab-59e6-89dd-64a1c18fca59"
 LibGEOS = "a90b1aa1-3769-5649-ba7e-abc5a9d163eb"
 Literate = "98b081ad-f1c9-55d3-8b20-4c87d4299306"
 Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"

diff --git a/docs/make.jl b/docs/make.jl
@@ -26,20 +26,20 @@ examples = [
     "orthographic.jl",
     "geostationary_image.jl",
     "multiple_crs.jl",
+    "rasters.jl",
     "is_it_a_plane.jl",
     joinpath("cartopy", "annotation.jl"),
     joinpath("cartopy", "katrina.jl"),
     joinpath("cartopy", "arrows.jl"),
     joinpath("cartopy", "vesta.jl"),
+    joinpath("cartopy", "streamplot.jl"),
     joinpath("gmt", "antioquia.jl"),
     "german_lakes.jl",
     "field_and_countries.jl",
     "meshimage.jl",
     "projections.jl",
     "tissot.jl",
     "rotating_earth.jl",
-    "rasters.jl",
-
 ]
 example_dir = joinpath(dirname(@__DIR__), "examples")
 for filename in examples

diff --git a/examples/cartopy/streamplot.jl b/examples/cartopy/streamplot.jl
@@ -0,0 +1,48 @@
+# # Streamplot
+
+# This example was translated from the [Cartopy streamplot example](https://scitools.org.uk/cartopy/docs/latest/gallery/vector_data/streamplot.html#sphx-glr-gallery-vector-data-streamplot-py).
+
+using CairoMakie, GeoMakie
+using Interpolations # for Streamplot on gridded data if necessary
+
+f(x::Point2{T}) where T = Point2{T}(
+    10 * (2 * cos(2 * deg2rad(x[1]) + 3 * deg2rad(x[2] + 30)) ^ 2),
+    20 * cos(6 * deg2rad(x[1]))
+)
+
+pole_longitude=177.5
+pole_latitude=37.5
+fig, ax, plt = streamplot(
+    f, 311.9..391.1, -23.6..24.8;
+    arrow_size = 6,
+    source = "+proj=ob_tran +o_proj=latlon +o_lon_p=0 +o_lat_p=$(pole_latitude) +lon_0=$(180+pole_longitude) +to_meter=$(deg2rad(1) * 6378137.0)",
+    axis = (;
+        type = GeoAxis,
+        title = "Streamplot",
+    )
+)
+lp = lines!(ax, GeoMakie.coastlines(); linewidth = 0.5, color = :black, xautolimits = false, yautolimits = false)
+translate!(lp, 0, 0, -1)
+fig
+
+
+# ## Gridded data
+# You can also do a streamplot on gridded data via Interpolations.jl:
+using Interpolations
+xs = range(311.9, 391.1, 100)
+ys = range(-23.6, 24.8, 100)
+uvs = f.(Point2f.(xs, ys'))
+#
+uv_itp = LinearInterpolation((xs, ys), uvs)
+#
+streamplot(
+    x -> uv_itp(x...), 311.9..391.1, -23.6..24.8; 
+    arrow_size = 6, 
+    source = "+proj=ob_tran +o_proj=latlon +o_lon_p=0 +o_lat_p=$(pole_latitude) +lon_0=$(180+pole_longitude) +to_meter=$(deg2rad(1) * 6378137.0)",
+    axis = (;
+        type = GeoAxis,
+        title = "Streamplot on gridded data",
+    )
+)
+# and it looks pretty much the same!
+