How to georeference an image with QGIS! 

THANK YOU!

Thanks @pubudunipun, I've actually been meaning to add a comment about that!

Interesting question! One approach would be to import the antique map to the map canvas as a raster (without a coordinate system) and georeference a raster representation modern map projection to the antique map. However I think this task is more suited to the general case of image registration, using something like MATLAB, NiftyReg, OpenCV or scikit-image in Python.

@@CapeRADD Thank you for your reply, I will give it a shot. Was hoping I could somehow use the .points data that was created when georeferencing the antique map. Was looking in to QGIS - GDAL - Warp, I believe it allows you to write a script in Python and reproject. Unfortunately is outside of my skillsets.

Exactly! Most GPS data will use the WGS84 coordinate system, but in South Africa for instance, surveying and engineering data might use the Hart94 reference system. These are geographic coordinate systems (they exist on a sphere). UTM zones are a projected reference system (they exist on a plane) and can be useful as the unit of measure is the meter, rather than degrees latitude or longitude, so measurements like length and area are more meaningful!

Thanks for the comment! I do this all the time. There's an option to add the georeferenced image to your map canvas that is easy to overlook. Look for "Load in QGIS when done." at the bottom of the transformation settings. You can also manually add the image to your canvas as a raster using the Data Source Manager. If the georeferencing was successful, you should be able to find it where it was saved.

@@CapeRADD Thanks. I did have that checked but it was not showing up. I figured it out though. I had to go back to the new raster layer and set the CRS for it.

It is no longer necessary to activate it as a plugin. The Georeferencer is now included as part of QGIS core. Simply look for the menu item under the Raster menu.

Hi Louai, There isn't a straight-forward way to drag the georeferenced image around that I'm aware of, but you can adjust your control points and perform the geo-referencing again to try and place it more accurately.

You would have to save that screenshot as an image using some kind of image editor like Gimp or MS Paint. However, QGIS 2.18 and above allow connections to a Tile Server like Bing or Google Maps. This stackexchange answer nicely documents how. gis.stackexchange.com/questions/20191/adding-basemaps-from-google-or-bing-in-qgis/217670#217670

@@CapeRADD thank you I have finally managed to achieve something! So I have added in all the google satellite and google topo maps as layers now, so I presume these are all georeferenced ? Also my coordinate system in the bottom right is EPSG 32629. I am in Ireland and want to use the Irish Trans Mercator system... I could not find it in QGIS, so could you point me in the right direction. One more question... in Ireland we have old 6" maps from the 1800's which are really handy for looking at old field boundaries etc. Would you know where I would go to get the Urls for these? Thank you your video was great.

@@melindaswann2018 If you added the images from the XYZ Tiles browser entry, then they are automatically georeferenced. EPSG 32629 is a UTM (Universal Transverse Mercator) projection valid between 12W and 6W in the northern hemisphere, which includes Ireland. It might actually be what you had in mind? As far as the historic maps, I'm not sure. You'll have to find someone who has digitised them. Maybe a local University library?

@@melindaswann2018 Looked into it a little further. 32629 isn't the ITM. The EPSG code for ITM is EPSG 2157

convert it into a pdf first

Depending on where you got the LANDSAT image, it should already be georeferenced! It's been a while since I've used any LANDSAT stuff, but I'm sure EarthExplorer was providing GeoTIFF files

The tool can be found under the Layers menu in more recent versions of QGIS

Thank you, but the purpose of this video was to show how you would georeference an image that does not have an embedded coordinate system.