How to paste pictures into data frame?

Question

I have a polygon feature class and I want to trace (select with a polygon) a picture that is solely comprised of a couple of interlocking letters.

In ArcMap when I would do this I would simply drag the picture into the data frame and I could adjust the sized and position of it, trace, export, delete the picture and have a brand new layer in the shape that I wanted.

I don't see a way to do this in QGIS, when I drag a photo in I am then prompted to define the new layer's coordinate system. It doesn't seem to recognize that it is only a picture. Anyone know how I can simply drag in a picture to QGIS to trace it?

Answer 1

Solution 1

If the picture has the size of the canvas, you could make a screen shot of the current canvas with file -> Save as Picture... . You get a world file (.jpgw or pngw) along with that picture.

If the size of the external picture does not match, use gimp to make it fit into it.

Just copy the world file and rename the first part to the name of the external picture you want to insert.

Insert that picture as raster layer, and choose the same CRS as the project has.

You get something like:

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Solution 2

Georeferencing by selecting four points on the canvas should work as well:

Load the gif in the georeferencer, choose the same CRS as your current project (noted in the status bar), click near one corner of the picture, select to get coordinates from map and click there, and so on for all edges.

The points on the map should have nearly the same ratio (heigth/width) as the original picture.

Click on the yellow icon to set the new filename and again the CRS, then the green triangle icon to start the georeferencer.