This is not meant to be a step by step guide.
The easiest way is perhaps just use our iPhone, the pictures are geotagged unless you turn off the location thingy in the setting.
I think many years ago I tried that already. Back then I was using an Android phone and some Nikon D7000 camera I believe. But things haven't changed much for me since then: my cameras still lack GPS. I still don't have any commercial reason to geo tag my pictures other than I feel like to and because I can. When exporting my pictures to JPEG, my routinely remove GPS data even I don't have them to begin with.
One of the few things I discovered is that Lightroom enables me to geo tag my pictures with the Map module (or whatever parlance Adobe uses).
So all I need is a software that allows me to create a GPX file from my iPhone. I just downloaded one from Open GPX Tracker. I proceeded to set the camera clock closest possible to my iPhone's as I suspect time will be used to match the picture taken to the gpx file time data.
Once I got the GPX file to my computer and Lightroom can just use some magic to get the GPS data to the picture files. If I don't want to be precise I can perhaps just drag whatever pictures to a location that's close enough without even the use of any GPX files.
So I just save myself some $90. Adorama used department sells some GP-1 for $59 or so without explicitly stating whether cable included or not so I take it it doesn't while KEH sells one for some $90 with cable included. I checked NikonUSA, the cable is selling the cable for $69.99 while I don't seem to find any pricing for the GP-1 or GP-1A, I think the 1A is the latest model and NikonUSA doesn't bother to say the difference. I have to find it out with a Google search. The 1A has some bigger screw on for better secured connection ... or something but feature wise, they are the same. Anyway I won't be buying one with or without the cable.
