I have a map in Adobe Illustrator with several vector layers. ( Therefore the vector data have no spatial reference and no attributes. What is the best way to turn these vector data into a GIS and therefore get spatial data? (for example in QGIS)
Georeferencing in QGIS is done with the plugin ‘Georeferencer GDAL’. From your top options bar: Raster > Georeferencer > Georeferencer. From the pop up box: File > Open Raster. Select the Coordinate System you'd like to use, use the filter option if you are not immediately seeing what you're looking for. The image you are trying to georeference will load in the top panel. Now to add your georeferencing points. Use the add points button, and put in the coordinates. Repeat the process at least four times. The more points the better it will align with the coordinates. When you have all your points: Settings > Transformation Settings. Fill out the pop up box. Transformation type. I used Thin Plate Spline and it worked well. Name your output raster and pick a Target SRS. Check the Load into QGIS box. Ok. Back to the Georeferencing Panel: File > Start Georeferencing. The output will be a correctly Georeferenced layer in QGIS.