The metadata section of digital photo files is not only capable of storing tags, keywords, camera and lens details, and shooting conditions. It is also can store a location of a photo. Such location data opens a lot of new ways to search for images, organize photos and browse. This section of the User Manual explains all features that Phototheca has to work with photo location data.
Types of location data. GPS and IPTC.
There are two standards of location data that Phototheca can work. They are GPS and IPTC.
GPS
GPS stands for Global Positioning System. This standard operates with a geographical coordinate system, and the location of a point in space is described by its longitude, latitude, and altitude. Nowadays, almost every gadget – cell phone or digital camera- is equipped with a GPS receiver chip to track a device’s location on Earth’s surface. A device’s current coordinates are embedded into a digital photo’s metadata section when you take a picture. The GPS data set may vary slightly from device to device, but usually, it includes latitude, longitude, altitude, time, speed, and view direction(like on a compass). This data is enough to pin a photo on the world map and even find an address of a location or its name within Phototheca.
So, GPS metadata is a set of numbers and usually looks like this:
IPTC
IPTC stands for International Press Telecommunications Council. This standard defines a set of metadata properties that can be applied to images. The standard describes dozens of different fields that can be utilized to store metadata inside images. Regarding location data, IPTC has four fields that describe a location where a photo was taken. The fields have a hierarchy, and they are:
- Sublocation
- City
- State/Province
- Country
While the last three are self–explanatory, the Sublocation field has no strict purpose and is pretty flexible to save anything. Sublocation could be the name of a specific area within a city (Manhattan) or the name of a well-known location (Pyramids of Giza), or a monument or natural feature outside a municipality (Grand Canyon, Mont Blanc Peak). If a photo is taken in a town or a village, the Sublocation can contain a regular street address or venue name(restaurant, shopping mall, office building, park, etc.).
Relation between GPS and IPTC
There is no relation between GPS and IPTC metadata. These sections are independent of each other. An image file can have them both, or has no any, or has one of them. Phototheca can read, write and change both GPS and IPTC sections in the most efficient way.
Import and export location data. Transferability of geo-tags.
Phototheca looks for GPS and IPTC sections in the file’s metadata on photo import and imports those sections into its library if there are any valuable and valid data. Phototheca can read and consume location data if photos are geo-tagged with another software, like Adobe Lightroom, Picasa, or Windows Live Photo Gallery, or geo-tagged by a device – cell phone or digital camera.
When you tag a photo with GPS and/or IPTC data within Phototheca, the application writes this data back to the image file in a proper format. This means all geotags added with Phototheca can be read by any other software that can work with geotags.