Which GPS datalogger can I use for automatic geotagging anyway?
Actually you can use any GPS datalogger. However, two things are important:

After being started, a datalog GPS receiver starts recording the position, date, and time. This information is part of the GPS signal. Various formats are used for recording. One of these formats is the standardized NMEA 0183 (National Marine Electronics Association) data format.

The locr GPS Photo software uses exactly this format. But, that doesn´t mean that you cannot use log files which have been created in another format. You simply have to convert them first. Therefore, save them e.g. on the hard disk, and then convert them with a suitable software like GPSBabel into the NMEA format. For information on special settings for locr GPS Photo have a look at "What is important in GBSBabel to save a gpx file in nmea format for locr GPS Photo?"

Then, you can settle back, and let the locr GPS Photo software do the automatic geotagging!

For detailed information have a look at:
"How can I geotag my photos with the locr GPS Photo software?"