I am trying to import this map to create models of the buildings that used to be there. I’m confused as to which steps I should follow. When I import it I seem to lose the georeferencing. Any advice appreciated.
https://collections.leventhalmap.org/search/commonwealth:1257c449t#image
I started with Google Earth and created placemarks at two intersections (Cambridge & Grove / Cambridge & Staniford). Using the GPS location of the first placemark, I manually geolocated the model at 42.361142N, 71.068739W. Next I imported the high-res map of old Boston and used the distance between the two intersections to scale the model. Then I imported a screenshot from Google Earth and aligned the map with the placemarks to get the North/South orientation corrected. Lastly, I added a building (garage) and exported the model as a KMZ.
Importing it into Google Earth gives this:
The model is too large to post here, but you can download it from the Warehouse:
BTW, the Warehouse page for this has a “Geolocated … Yes” property that gives this:
Hope this helps 
Thanks so much. I appreciate your time. For clarification, does it matter to this method whether or not the map has been georectified before, or would it be basically the same if you were using a regular .jpg of a map?
For small areas, it doesn’t seem to matter much. However, larger areas may be off by quite a bit depending on the GIS coordinate system used. SketchUp and Google Earth usually work well together while Google Maps appears to map things slightly differently.
You could also just directly import the Google Earth ground overlay and placemarks into SketchUp without the detour of manual scaling and alignment using this extension: [Plugin] KML Tools (2.0.0-beta) — updated 31.05.2013 • sketchUcation • 1
(Although if the demand actually exists, someone should maybe update it who has a real use for it.)
I misunderstood your question 
The process I described works with any image or map, but alignment is always a bit tricky. I used the 10MB JPEG file to create the geo-located model. A better solution might be to find a converter to convert the 166MB GeoTIFF file to KMZ and then import the KMZ file directly into SketchUp.
It is a common misunderstanding that SketchUp would generally support .kmz (Keyhole/Google Earth) files. It does unfortunately not. It can only read .dae (Collada) model files which may be packaged in a .kmz archive. SketchUp’s built-in kmz importer is little helpful for geographic data if it is not a 3d mesh.
