Reply With QuoteThere's no easy way to do this. You have to extract the geometry from the map as GIS vector data, georeference it, reproject it, and then style it as a new map.
Change map projection of vectorial maps
The question is simple but I cannot find an easy answer, so I'll ask you.
How do I change map projection of a vectorial equirectangular map? The maps are made on Illustrator. The world is created and invented so I have difficulties in understanding how to use GIS programs for my specific use.
Thank you for the answer
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There's no easy way to do this. You have to extract the geometry from the map as GIS vector data, georeference it, reproject it, and then style it as a new map.
where can I learn to do this? And can be done maintaning the vectorial nature of the file?Originally Posted by Hai-Etlik
Last edited by Impesio; 01-05-2019 at 11:32 AM.
My Deviantart: https://impesio.deviantart.com/
Are you just looking to project the map image into another projection? Or are you looking to transform the actual vector data into a new projection?
If all you're looking at doing is projecting the map into a new projection, for example going from Plate-Caree to Robinson, then you should take a look at NASA's G Projector software (https://www.giss.nasa.gov/tools/gprojector/). It can perform any data projection tasks you need completed.
If you actually want to transform the vector data into a new projection, I would recommend that you start by looking at QGIS (https://docs.qgis.org/2.8/en/docs/ge...ion/index.html) and seeing what it can do.
qgis uses GDAL to do the map projections , it uses raster images
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GIS vector data is quite different from vector graphics data. It's still vector in the abstract sense that it represents shapes as sets of coordinates and connections between them but the way it does so is different, and they don't store information about visual presentation as that is handled separately via styles, sort of like web pages, at least in the very rare situations where web pages are actually done correctly. So this will still be "vector" but it will be a VERY DIFFERENT vector from what you are used to.
Actually converting a vector graphics map into raw GIS data is not straightforward and isn't something that's done very often. So there's not enough demand for specific tools or explanations, and even if there were, each image is different so you really have to come up with the process on a case by case basis. You really have to understand the particular vector graphics tools and formats you are using and the particular structure of the specific image, and then do a bunch of processing to extract the information into something cross compatible between graphics and GIS like a DXF file.
You'd probably be better off saving a raster image, loading it into a GIS, georeferencing that, and then tracing out the vector shapes as vector GIS features. If you can extract the distinct feature sets this will be easier and you might be able to automate it somewhat, although you will probably have to do some manual cleanup.
GDAL is not confined to raster since merging with OGR, and even when it was, QGIS also used OGR for dealing with vector datasets. I think in some cases it also uses Proj.4 directly without going though GDAL/OGR. QGIS most certainly does reprojection of vector GIS data.
There is a small chance that you might be able to get your image by using the PDF facilities of GDAL (you can read the PDF, reproject it, and then generate a new PDF or other file). However, you need to specify your own projection information for the source file, which can get ugly. I have never tried to do this with QGIS.
Thank you for all your answers!
My goald would be to make a world map in illustrator and try to reproject it to make more definite and precise drawing on the pole and use this map to eventually make regional or continental maps.
My Deviantart: https://impesio.deviantart.com/
Reprojecting a "map" is where you are going to run into problems. Finished maps are not amenable to reprojection. It's far better to take raw data, project that, and then make a map from it. Then project it again differently, and make a different map in the new projection.
To do this with vector data it would be best to use something like QGIS to create a raw dataset in a format like a GeoPackage. You can then adjust things until it looks right in various projections, select the projections and layers you want for your maps, and then export as SVG or PDF to load into your graphics software to pretty up.
Note that QGIS's vector output is semantically "messy" in that it doesn't arrange things in nice groups or layers for easy editing or use things like stylesheets or object references. From what I've heard from QGIS developers, they use a plugin to QGIS's QT based rendering path that converts QT commands directly into an appropriate vector image file. This ensures that the appearance is as consistent as possible between what you see on screen in QGIS, and what you get in your image file without having to maintain two complete rendering pathways. The downside is that there is no way get that semantic structural information through such a process. Fixing this would require a completely new rendering system for QGIS.
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