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I have built and maintain a SWTOR game map atlas. At the moment, it's all static jpg maps, but I would like to get the info into an actual GIS software to get more functionality and make my website more mobile-friendly.

I assume the first step is to get the game map into a GIS software. I have a png of the map, and I have game map coordinates for a few points on that map. I used the QGIS georeferencer plugin; however, no matter which projection I choose (I tried UTM 19N, UTM 1N, custom eqc I found in this post, even EPSG 2046), my map always shows upside down and/or inverted left-right.

I've read around the internet quite a bit, but still don't understand what I'm doing wrong.

What projection should I be using? Is there a way to define a custom projection and control which axis is pointing upwards (I tried +axis=end without luck)?

For extra clarity, the map: Tython map before georeferencing attempt

And the result after attempting to georeference with UTM 1N (same effect with ALL projections I tried): Map after georeferencing attempt

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  • Generally images are referenced from their upper left hand corner and cell size is negative (see webhelp.esri.com/arcims/9.3/General/topics/…). As for a reference I don't know what you'd use but I assume you're either inside a zone (6 degrees wide) or multi-country.. if you've got maps in metres (or feet) a NAD projection might be able to mimic the behaviour you want, for larger scales in metres use either Albers Equal Area or Lamberts Conformal but it would be best to use degrees instead of metres - either geographic (like WGS84/DD) or mercator (for true bearings).
    – Michael Stimson
    Sep 2, 2015 at 3:08
  • This is a bit tricky, all projections I use are for y axis growing up (North). Where your map have coordinates growing down (South). Not sure if there is any projection for that. If not, it will be necessary to switch +/- of your Y coordinates when georeferencing so the image is not upside down and then tweak any web solution you use to show live coordinates as multiple of -1.
    – Miro
    Sep 2, 2015 at 4:09
  • Could you be more clear on how you want to present your maps on the web and how users will be using them?
    – Techie_Gus
    Sep 2, 2015 at 6:33
  • Michael - I've stumbled upon that page before but, I'm sorry, I don't know what a world file is. Is it something that the QGIS georeferencer uses? Miro - There are a few south-up projections (EPSG 2046 is one, if I understood correctly), but even using them my map always ends up flipped in some way. Thechie - I haven't decided yet on the web part of the thing; I was tentatively considering a WMS-type solution. For now I'm just trying to see if I can process this data with a standard GIS workflow.
    – Melodie
    Sep 2, 2015 at 12:57

1 Answer 1

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First, I'm not sure what kind of axis order that your games uses, but sometimes maths stuff uses X and Y at zero on the top left, and increasing right and down respectively.

Note that GIS uses X and Y a 0 at the bottom left, and increasing right and up. I think you should be able to swap the Y coordinates in your georeferencing points and be good to go.

Keep in mind your target system.

I reckon you want to use Leaflet to present your map, if you're presenting it on the web. If so, perhaps play around with the image overlay function. That will get your image directly into Leaflet. You can then use some of the draw and save geojson functions to write points and lines that can be displayed too. Or do this in QGIS and save them out as GeoJSON. You might use your foggy background as an image, and the 'masters retreat' and other features as points with a nice symbol, with interactivity.

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  • I'm not sure I understand what you mean by "swapping the Y coordinates"... You mean manually inverting the sign? I can't do that, because then people would see on my map coordinates that wouldn't fit with what they have in game. Also, not all planets have the same direction of growing coordinates, but they ALL show upside down in some way. I have to be able to control coordinate directions in the projection.
    – Melodie
    Sep 2, 2015 at 2:26
  • I mean where you have the lowerleftX and lowerleftY, and upperleftX and upperleftY, swap the llY and ulY coordinate values. If your game uses coordinates that are in the other direction, then I'm not sure how to sort that out in a GIS, unless you have some kind of inversion method.
    – Alex Leith
    Sep 2, 2015 at 3:48
  • Ah, okay, thank you for the precision. However, on another planet, X grows towards the right and Y grows towards the top (standard situation). But even THAT map ends up flipped left-right, which is why I don't understand what is going on.
    – Melodie
    Sep 2, 2015 at 13:01
  • Thank you, it seems I will be multiplying all Y coordinates by -1 before putting them into GIS, and multiplying by -1 again when I take them out for display to users.
    – Melodie
    Sep 2, 2015 at 19:01

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