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I'm currently creating a worldmap. For technical reasons, I want to do it on a computer, as a vectorial image (I can't use pixel images because I need small details).

For more accuracy, I want to have a mastermap with equirectangular projection, and then convert some small areas of it to stereographic projection to be able to work on them with minimal distortion. When I'm finished with an area, I'll convert it back to equirectangular projection, to "stick" it on the mastermap.

However, I haven't found any way to convert vectorial maps (they are svg files) from equirectangular projection to stereographic projection, and vice-versa. I found some projection converters for pixel images, but they don't work with vectorial images.

So, does anyone know any software or any way to convert vectorial maps to different projections? Thanks.

Post-scriptum: I mainly use Inkscape.

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  • $\begingroup$ Do you have a favored vector drawing software? Just in case someone has the perfect module you need on this software, or a peculiar technic to achieve the same result. $\endgroup$
    – Tortliena
    Dec 8, 2022 at 16:54
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    $\begingroup$ @Tortliena I use Inkscape. $\endgroup$
    – Desktop Firework
    Dec 8, 2022 at 16:56
  • $\begingroup$ You are very likely to get more and better help on a forum dedicated to maps and such. There are places that discuss the various natures and glitches of Google maps for example. It's a software and geometry issue, not really what we do here. $\endgroup$
    – Boba Fit
    Dec 8, 2022 at 17:29
  • $\begingroup$ Asking for help finding resources to facilitate Worldbuilding is a legitimate question on this site. As the respondents have mentioned, you're asking for a bit more than usual because the convenience you're seeking is usually the domain of professional geosurveying software. However, we're always looking to improve our list of Worldbuilding Resources, so I'm keeping track of this question to improve that list. $\endgroup$
    – JBH
    Dec 14, 2022 at 22:40

2 Answers 2

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The only full solution I can think of is to use a real GIS package, such as QGIS.

As a palliative, which may or may not be good enough, if your drawing software of choice allows you to render only a part of the drawing, then one way is to render the map or any part of it as a raster image to a suitable scale for the level of detail, and then use a tool like NASA's G.Projector to convert from equirectangular to the projection of your choice. (G.Projector lets you specify the bounding coordinates of the equirectangular map you import.) In this way you can have a world map with not so many details, and then zoom in to some selected parts with more level of detail. But unfortunately this works only one way...

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This is more a GIS question then anything.

Unfortunately most of the info for importing svg into QGIS is about symbols. A quick google suggested exporting to DXF, which can be imported into QGIS. Once it is in QGIS, then you can use its tools to re-project or just change the project projection to have it change on the fly. There seems to be a plugin that allows you to convert vector layers to svg. I have not used it.

Alternatively, you could create a script that would parse the svg, find points reproject them then write out modified svg. To do the projection use something that has bindings to the "proj" library eg. pyproj for python.

Alternativly there are tools such as cs2cs from the 'proj' project.

cs2cs "EPSG:26910" "WGS 84" 541549 5446510 49d10'11.986"N 122d25'48.06"W 0.000'

Consider changing your workflow to be GIS friendly. Since the question effectively states you are doing GIS work. Using tools built for the job may make things easier in the long run.

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