Creating maps when crossing the datelineI have a very unusual issue that is surely NOT to be very widely applicable: I am working with samples obtained very close to the international dateline (Fiji). When I go to overlay the data onto a map using pre-created shape files (one feature I love about JMP, BTW), it basically plots them on opposite sides of the globe, rather than center them around the 180 degree dateline. Upon a quick Googling, I noticed that this is an issue in other graphing software. I tried changing the access to geodesic, but this did not help. I tried to make a plot and place a background map of FIji behind it to see if this would do the trick, but it basically would not load the map! Any thoughts?
Re: Creating maps when crossing the datelineGreat! It worked this time. The only weird thing is that, rather than go to 178, it instead goes to -182, despite being on the geodesic setting. Actually, that might be part of the geodesic system: plotting from 0 to 360, rather than -180 to 180. It actually makes more sense the former way! But I should be able to change to the more traditional -180/180 easily in Adobe Illustrator.
Re: Creating maps when crossing the datelineYes, that's correct. Notice that the Latitude axis is going from -163 to 125. Adjust it to zoom in to the range of your actual data. I add a background map below just to make it clearer whats going on.
Re: Creating maps when crossing the datelineIf I set both to axes geodesic, I get the attached image. I also tried geodesic US, but the outcome was the same. In any event, it's not hard to add 360 to the negative values, so I think I can just do that.
Re: Creating maps when crossing the datelineThat's what you get if you only set the Longitude (X) axis to Geodesic.
You need to set Latitude (Y) to Geodesic also.
Re: Creating maps when crossing the datelineNow something is really going on with my graph: the longitude doesn't "wrap" at 180 but keeps going and going. Therefore, centering it at -180 degrees still gives a non-real presentation. It seems like changing the setting to "geodesic" should fix this?
Re: Creating maps when crossing the datelineSorry, I forgot to mention that you need to adjust the longitude (x) axis so that -180 is in the middle.
Re: Creating maps when crossing the datelineJeff,
Your data table plots correctly, but for some reason mine does not. Maybe I input something wrong? If you plot latitude versus longitude using in this table, they are plotted on opposite sides of the globe, even when set to geodesic!
Re: Creating maps when crossing the datelineActually, I'm curious about the problem that you're seeing as it works for me if I've got the Geodesic axis scale on both X and Y.
Try the attached data table and the script in it and see what you get.
Here's my result.
Re: Creating maps when crossing the datelineGreat! This seems to do the trick. I'll just need to manually change the y-axis (i.e., longitude) when I go to make the actual figure (i.e., convert 181 degrees back to -179). Thanks.
Re: Creating maps when crossing the datelineAdd 360 to the negative longitude.
formula to add 360the image maps wrap but the outlines do not.
outline does not wrap
