A physical giudebook is as only good as its author. In the old days of hand drawn topos, the climber would be often lost staring into the wood trying to align their compass to the hidden boulders in the forest.
Now that satellites are buzzing above taking high resolution photos, providing triangulation for device location services and mapping apps in your pocket. The modern climber has vast resources to locate effortlessly most anything lurking the forest.
Each area in the guidebook has a quick link back to this site. From there you can click the little map icon in the top to launch a google map. This will provide surface details of the area with the same pins as each boulder provides.
If you open this in the Google Maps app you can use your location to the boulder. Easy as that. Incase you don’t know what the boulder should look like the same photo from the guide is attached.
Good luck out there.