The interactive map below is one of the electronic features in Thomas Bruce Wheeler's The Mapped London of Sherlock Holmes, available at Amazon and Barnes & Noble ($5.99). You can preview the map by a mouse click on one of its Sherlock Holmes symbols. If you wish, the legend on the left side of the map can be collapsed by clicking on the legend's small vertical three-dot symbol. Then, a mouse click on any of the map's Sherlock Holmes figures will open an illustrated text box explaining that site's Sherlockian significance.
If you want to see a photograph of that place, click on the small diamond symbol on the text box. This will open a new Google map with only that site marked. There is a small yellow Pegman symbol on lower right of this new map. Click and drag the Pegman to the blue street nearest the marked site. This will produce a street-level photograph. The mouse wheel can then be used to convert the photo to an aerial view.
The Mapped London of Sherlock Holmes e-book also contains access to a map of Victorian London. A mouse click on the book's cover below, will link to Amazon.com. There, their "Look inside" feature will allow you to preview all of the book's computer app features. For example, the book provides GPS addresses so that London visitors with a GPS app on their smart phone can get walking instructions from one Sherlockian site to the next.