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plotting - Using map projections with astronomical data


I noticed that all important "Geoprojections" are available in projections for a spherical reference models: GeoProjectionData function;


1 - I am trying using the sinusoidal projection for astronomical data purposes. I want to use the frames of this projection to plot astronomical points in that map , using right ascension and declination as the coordinates, both in degrees.


In the link below, is a data that can be used, the format is { {RA,DEC, Velociy},....}. Just need the RA, DEC parameters.


DataSample


a. I got the data in {Dec, Ra} :


p = Reverse[#] & /@ rad[[All, {1, 2}]]

b.then I transformed the parameters DEC RA, to sinusoidal numbers:



dat = GeoGridPosition[GeoPosition[p], "Sinusoidal"][[1]]

c. I did the following code:


 GeoListPlot[dat, GeoRange -> All, GeoProjection -> "Sinusoidal", 
 GeoGridLines -> Automatic, 
 GeoGridLinesStyle -> Directive[Dashing[{0.0005, 1 - 0.9950}], Green],
  GeoBackground -> Black, Frame -> True, 
 FrameLabel -> {"RA (\[Degree])", "DEC (\[Degree])"},  
 PlotMarkers -> Style[".", 10, Red]]


And the resulting plot is:


SINUSOIDAL PROJECTION PLOT


But no data was plotted.


And the ranges of Frame Axis are wrong: the horizontal axis has to be middle to left 0 90 180, and middle to right 0 (or 360) 270 180.


In the Vertical Axis: -90(bottom) 0(center) +90(top)


EDIT 1:


The link to wolfram math world about sinusoidal projection : Sinusoidal



Answer



Edit: for general approach to Ticks, go there: GeoProjection for astronomical data - wrong ticks




data = Cases[ Import[FileNames["*.dat"][[1]]],
              {a_, b_, c_} :> {b, Mod[a, 360, -180]}]; (*thanks to bbgodfrey*)

To show points you have to stick with GeoGraphics. GeoListPlot is designed for Entities.


To add something more to the question I changed Ra to hours.


    GeoGraphics[{Red, Point@GeoPosition@data}, 
      GeoRange -> {All, {-180, 180}},
      PlotRangePadding -> Scaled@.01,
      GeoGridLinesStyle -> Directive[Green, Dashed], 
      GeoProjection -> "Sinusoidal", 

      GeoGridLines -> Automatic, 
      GeoBackground -> Black, 
      Axes -> True, 
      ImagePadding -> 25, ImageSize -> 800, 
      Ticks -> {Table[{N[i Degree], Row[{Mod[i/15 + 24, 24]," h"}]}, {i, -180, 180, 30}], 
                Table[{N[i Degree], Row[{i, " \[Degree]"}]}, {i, -90, 90, 15}]}, 
      Background -> Black, 
      AxesStyle -> White, 
      TicksStyle -> 15]


enter image description here


Or change every option with Axes to Frame and:


enter image description here



With coloring:


pre = Cases[ Import[FileNames["*.dat"][[1]]], {a_, b_, c_} :> {b, Mod[a, 360, -180], c}];
data = pre[[All, {1, 2}]];
col = Blend[{Yellow, Red}, #] & /@ Rescale[pre[[All, 3]]];




GeoGraphics[{AbsolutePointSize@5, 
  Point[GeoPosition@data, VertexColors -> (col)]}, ...

enter image description here



pics = Table[
   GeoGraphics[{AbsolutePointSize@5, 
     Point[GeoPosition[{#, Mod[#2, 360, -180 + t]} & @@@ data], 
      VertexColors -> (col)]}, PlotRangePadding -> Scaled@.01,

    GeoGridLinesStyle -> Directive[Green, Dashed], 
    GeoProjection -> "Bonne", GeoGridLines -> Automatic, 
    GeoBackground -> Black, ImagePadding -> 55, ImageSize -> 400, 
    GeoRange -> "World", GeoCenter -> GeoPosition[{0, t}],
    Background -> Black, FrameStyle -> White, FrameTicksStyle -> 15],
   {t, -180, 170, 5}];

Export["gif.gif", pics, "DisplayDurations" -> 1/24.]

enter image description here



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