I want to add a classification to photos which are in an excel spreadsheet within a KML file.
Need a way to combine/join fields that are in an Excel spreadsheet to a KML file.
It should be possible with the open-source program QGIS. I recommend installing the LTR (long-term release) version, QGIS 2.18, because the documentation is much better than for the newest version.
Save the Excel file in CSV (comma-separated value) format.
Load the KML into a QGIS project.
(optional, but a good idea) Install the plugin QuickMapServices, and use it to add a basemap to your project. Compare the KML to the basemap and make sure it's in the correct location. If it's not, do not proceed until you resolve the issue. Otherwise your final export will be incorrectly geolocated.
Load the CSV file as an attribute-only table in the same QGIS project.
Join the table to the KML.
Export the joined layer in KML format.