Trying to Rotate the North Pole View of a Globe
Update: It turns out oblique "Orthographic"
projection (mentioned in the link provided by J.M.) has been implemented. Using the option "Centering" -> {90, - 30}
gives the desired rotation in OP's case without the need for ImageRotate
:
Row[GeoGraphics[{PointSize[Large], Point[fresno]}, ImageSize -> 300,
GeoRange -> "World", GeoGridLines -> Automatic,
GeoBackground -> GeoStyling["StreetMapNoLabels"],
GeoProjection -> {"Orthographic", "Centering" -> {90, #}}] & /@
{-30, -60, 45}, Spacer[10]]
Original answer:
fresno = Entity["City", {"Fresno", "California", "UnitedStates"}];
geog1 = GeoGraphics[{PointSize[Large], Point[fresno]},
ImageSize -> 400, GeoRange -> "World", GeoGridLines -> Automatic,
GeoBackground -> GeoStyling["StreetMapNoLabels"],
GeoCenter -> {90, 0}, GeoProjection -> "Orthographic"];
You can use ImageRotate
with GeoStylingImageFunction
as follows and post-process to rotate the Point
primitive:
geog2 = GeoGraphics[{PointSize[Large], Point[fresno]},
ImageSize -> 400, GeoRange -> "World", GeoGridLines -> Automatic,
GeoBackground -> GeoStyling["StreetMapNoLabels",
GeoStylingImageFunction -> (ImageRotate[#, 30 Degree, ImageDimensions@#] &)],
GeoCenter -> {90, 0}, GeoProjection -> "Orthographic"] /.
Point[x_] :> GeometricTransformation[Point[x], RotationTransform[30 Degree]];
An easier approach is to rotate Rasterize
d geog1
:
raster = Rasterize[geog1, Background -> None];
geog3 = Show[ImageRotate[raster, 30 Degree, ImageDimensions @ raster,
Background -> None], ImageSize -> 300]
Row[{geog1, geog2, geog3}, Spacer[10]]
rotate = ImageRotate[raster, #, ImageDimensions @ raster, Background -> None] &;
arrows = Graphics[{Arrowheads[.15], AbsoluteThickness[7], White,
Arrow[{Scaled[{2, #}], Scaled[{1, #}]}] & /@ (Range[4 ] / 5)}];
frames = Show[rotate[# Degree], arrows, Background -> Black,
PlotRange -> All, ImageSize -> 700] & /@ Range[0, 360, 10];
Export["rotategeog.gif", frames]
kglr's updated answer is the more correct option. My less correct answer follows.
There are two tricks here - one to be able to get the same image size regardless of background in the GeoGraphics, and another to use ImageCompose to place one image inside another.
Here we have a function to give back an image of the same size given any rotation. There's a bit of a hack here to make the background of the GeoGraphics
and the background of the ImageRotate
Purple
. Unfortunately when you use ImageRotate on a GeoGraphics, it appears to disregard the alpha channel and cast the background to white (even if you had it set to None
or Transparent
). We then replace all Purple
with Transparent
, to get a nice image we can compose with. You also use ImageCrop
to get a consistent image size.
rotateGlobe[d_] :=
ColorReplace[
ImageCrop@
ImageRotate[
GeoGraphics[GeoRangePadding -> 0, ImagePadding -> 0,
GeoBackground -> "Coastlines", GeoProjection -> "Orthographic",
GeoRange -> "World", GeoGridLines -> Automatic,
GeoCenter -> {90, 0}, Background -> Purple, ImageSize -> 400], d,
Background -> Purple], Purple -> Transparent]
We'll also define your "arrows" to make it more clear what we're doing.
arrows = Graphics[{Black, Rectangle[{-1.1, -1.1}, {6, 1.1}], White,
Thickness[0.01], Arrowheads[0.04],
Table[Arrow[{{6, y}, {1.1, y}}], {y, -1, 1, 0.5}]}]
And now we can animate the two together. ImageCompose
here is your friend, as you have two images with quite different dimensions. I used Scaled
a lot, eyeballing scale and position until it looked right.
Animate[
ImageCompose[arrows, ImageResize[rotateGlobe[d], Scaled[.25]],
Scaled[{.18, .5}]],
{d, -\[Pi], \[Pi], .1}]
or,
Table[
ImageCompose[arrows, ImageResize[rotateGlobe[d], Scaled[.25]],
Scaled[{.18, .5}]],
{d, -\[Pi], \[Pi], 1}]