I'm trying to input a .png map into my QGIS project for a small area in South Africa. I don't know the CRS used to create the map but it has a grid system on it with the lat/lon labelled (created using photoshop I think). I have numerous problems occurring:
- I've tried to georeference it using the "from map canvas" option and I added in 17 different points. But when I added it as a layer to my QGIS map (for which I have already input some of the roads, water sources, landmarks etc as vector layers on top of Google Sat/ Open Streetmaps) it places the map as a tiny tiny spec in the middle of the sea near Guernsey (British Isles)! I have no idea how this could happen. Is it something to do with the scale? When I created the georef map I selected "Linear", "Nearest Neighbour" and I set the CRS to the same as my project: WGS84 EPSG 3857 (OTF). When I "Zoom to layer on the layers I've created that fit with Google Satellite map the scale reads 2:1, when I "Zoom to Layer" on the georeferenced raster layer created from the .png map it reads 1:1.
- I could try and georef using the lon/lat on the .png map grid but they don't match up with the lon/lat when I hover over the same features on the map canvas. It's close but tens of seconds out (e.g. a landmark at E26•07'29.2, S33•30'27.3 on the png lies at 26.13072, -33.50735 on the QGIS map). The QGIS project is in WGS 84 Pseudo Mercator EPSG 3857 (OTF).
- The other option is to recreate the grid used on the PNG map (because the grid reference system from this has been used to record data in the field for this project) in the QGIS project but then I hit the same problem with the lon/lat not matching. AND, being a relative QGIS newbie I don't know how to create this grid in my project. Any tips?
Unfortunately I cannot share the map with you.