The McCann apartment was 5A. I have added a white dot (nearer the top) that is the front door and/or where Madeleine slept. The white dot a little below and to the right is the gate that opens to the rear stairs. Up the rear stairs is the patio, the patio doors, and the rear entrance to the apartment. In brief, the white dots are the entries/exits of a kidnapper, a burglar, or simply a child-watcher.
The four yellow dots are the street lights. These are all omni-directional, sodium (i.e. yellow) lights.
If you look at the two that shine on the front (top) of the McCann apartment, you should notice the flat was well hidden by trees. (The photo is around 6 weeks after Madeleine disappeared. An earlier, much grainier photo shows much the same trees.) It was after sundown, there was no moon at the time. The evidence suggests (still to be proved) that there was around 50% cloud cover, thus starlight added little. In brief, the front (top white dot) of the apartment was quite dark.
By contrast, the rear gate was lit up by 3 street lights, none of which was obscured by trees. Check the diagram again, and you’ll see that only one of these 3 lamps illuminated the actual rear of the flat. Of the 4 street lights, only the one at the south (bottom), casts light on the patio of the McCann apartment.
The two blue dots are the good guys. At the bottom blue dot is the Tapas restaurant. Further up and right the other blue dot is the only way in/out of the Tapas area. All the good guys have to do is to beat the bad guys, the white dots. This is the abduction theory.
The kidnappers have to make it (at least as far as) to one of 3 points to be safe with their quarry.
The red dot at the top is the entry to a footpath between two blocks of apartments. It is walled on both sides to a height that conceals everything. Baddies win.
The lower red dot is in the car park of block 6. Beyond that there is a rabbit warren of footpaths that lead here, there, and everywhere. Baddies win.
The third route is less likely. The kidnapper heads out of the McCann apartment to the north (top) and turns left. This fits well with the Smith sighting, in terms of layout, but it is visible from anyone doing a check via the front of block 5. In brief, it is unlikely.
You are now well acquainted with the outside of apartment 5A, and this information is vital to understanding what went on within 5A, the McCann apartment. It is now time to go inside.