Index

# Geocode from Reference Photos

The second, "yellow", step of geocoding consists of providing HoudahGeo with information on where the pictures were taken.

## Geocoding from Reference Photos

Many modern phones, like the iPhone 3G, have built-in GPS receivers as well as cameras. They take geocoded photos. Unfortunately photos coming from camera phones are often times low in quality.
HoudahGeo is able to use those geocoded photos as reference points when geocoding your regular photos. Indeed, when HoudahGeo sees that both a geocoded photo and one that isn't have been taken during the same time frame, it can assume that both were taken at the same location.
While taking photos, you should take one reference picture at each location where you stop. At each location you will also take a number of pictures using your regular digital cameras.
Back at home you will import all your photos into a single HoudahGeo project. You will notice that some are already geocoded, but most are not. Then you select "Geocode from Reference Photos" from the "Geocode" menu. You will be given the option to specify if the reference photos precede or follow the regular ones.
HoudahGeo can now propagate the GPS information from the reference photos to the remaining ones.
You may want to remove the reference photos from the project before proceeding to export photos.