GPS Functions

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Photo Mechanic has several functions for getting the most out of your photos with GPS coordinates. Global Positioning System, an accurate navigational facility based on the reception of signals from an array of orbiting satellites, provides photographers with the ability to locate where they created their photos. Some cameras have built-in GPS receivers on them and will automatically insert the GPS coordinates of the location where the photo was taken. Others have the ability to connect to a separate GPS receiver and will also insert the GPS coordinates of the photo’s location. Most cameras do not provide either of these services, but the emergence of relatively inexpensive GPS data loggers provides the same functionality but requires a little bit more work. Photo Mechanic provides an import function for this purpose.

Importing GPS Coordinates

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Given a selection of photos, the Import GPS Coordinates dialog can import GPS logs in the GPX and NMEA formats. In order to load your GPS logs, you need to copy your GPS log from your GPS data logging device to your computer’s hard drive, or if your GPS data logging device acts as a USB storage device (like the excellent AMOD AGL3080 device does) then you can access your logs directly. Use the ‘Add...’ button to choose and load your logs. Use the ‘Remove’ button to remove any added logs you no longer want to work with. Once all of your logs are loaded, use the ‘Plot GPS Logs’ button to plot the path you travelled on the Google map. Next you’ll need to synchronize the time your photos were taken with the GMT based times that are recorded in each GPS coordinate. The simplest way to do this is to use the ‘Auto’ button in the ‘GMT Offset of Photos’ section on the right side of the dialog. This automatic offset calculation uses the difference in time between the earliest coordinate in the GPS logs and the capture time of the first selected photo. This is often a very good time offset, but if you find that the GPS coordinate matches are not very accurate, use the remaining time/day offset fields to adjust to your liking. You can always use the ‘Reset’ button to start over. The buttons in the ‘Move through log coordinates by second’ box allow you to further fine tune your time offsets in a more intuitive manner. You’ll see the map markers change as you move through the log coordinates. To see different photos in your selection and where they match up, use the various ‘arrow’ buttons to navigate through your selected photos. Use the ‘Dismiss’ button to remove a photo from your selection. Once you’re satisfied with the matches, use the ‘Import’ button to bulk apply the coordinates from the logs to your selected photos.

There are three more elements in the Import GPS Coordinates dialog worth mentioning:

  • Allow matches within gaps in log: allows Photo Mechanic to ‘interpolate’ locations between two GPS coordinates. If this checkbox is turned off then only GPS coordinates with time matches within the time range specified will be used and some photos will not receive GPS coordinates.
  • Don’t match photos if closest log time is off by more than ‘N’ minutes: specifies the time range for matching GPS coordinates with photos.
  • Overwrite existing GPS coordinates in photos: allows GPS coordinates that may already exist in selected photos to be overwritten by the GPS coordinates being imported. If you don’t want photos that already contain GPS coordinates to be replaced by the imported GPS coordinates, then uncheck this checkbox. Only photos that do not have GPS coordinates will have GPS coordinates imported.

Setting GPS Coordinates

Photo Mechanic also offers the ability to manually add GPS coordinates to photos either singly, or in a batch. Use the ‘Set GPS Coordinates’ command on the ‘Image’ menu to bring up this dialog. GPS coordinates may be entered manually in the coordinate format of your choice or by using the Google map on the right side of the dialog.

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Use the ‘Show on map’ button to display coordinates you've manually entered to see if they're what you expected. Once you're happy with the location, use the ‘Accept’ button . Or if your coordinates apply equally to all of your selected photos, use the ‘Apply to All’ button to give all selected photos the same coordinates. Use the ‘Apply to Remaining’ button to apply the the photo below and the the photos that follow it in your selected set of photos.

For a more interactive approach, use the Google map on the right side of the dialog. You can enter points of interest, or full street addresses and then click on the ‘Get GPS’ button to look up the location and plot it on the map. To fine tune the location you can pan the map around and the marker will center itself at the new location, or you can pick up the marker with your mouse and drop it at the desired location. Once you’re happy with the location, use the ‘Accept Location’ button below the map to copy the location into the GPS Coordinates section of the dialog. You may now apply the location to one or more photos.

Use the ‘Arrow’ buttons to move through your selected photos, setting GPS coordinates as you go, until you have set them all. Use the ‘Close’ button to dismiss the dialog.

Visualizing GPS Coordinates

For viewing photos along with their location on a map, and Info Text use the ‘Show Map’ command on a Contact Sheet thumbnail’s contextual menu by right-clicking on a thumbnail (use Ctrl-click if you have a single button mouse). Note that this option only shows up when the selected photos have GPS info associated with them. This will display the GPS Map Browser like so:

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If you have selected multiple photos, you can quickly scroll through their positions with the arrow keys or buttons next to the map.

Another way to visualize your photos and their GPS coordinates is to download Google Earth from http://earth.google.com/ and then use the ‘KMZ’ Export template to create a KMZ file that you can open in Google Earth.

Setting GPS Home Location

Photo Mechanic also offers the ability to set a GPS location of your current base of operations. With a GPS home location, you can use some of Photo Mechanic’s variables to display useful information like distance and bearing of each photo relative to the GPS home location. The variables {distance}, {bearingfrom} and {bearingto} each have their use, but {distance} is immediately understandable and can be used for sorting of your photos by their distance from your GPS home location.

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You set your GPS Home location by using the Set GPS Home... command on the Settings submenu of the Edit menu. Choose a location by using either a selected photo, a manually entered GPS coordinate, or by using the Google map on the right side of the dialog. You can enter points of interest, or full street addresses and then click on the ‘Get GPS’ button to look up the location and plot it on the map. To fine tune the location you can pan the map around and the marker will center itself at the new location, or you can pick up the marker with your mouse and drop it at the desired location. Once you're happy with the location, use the ‘Accept’ button below the map to copy the location into the GPS coordinates section of the dialog. Click the OK button to accept the location.

Sorting by GPS Distance

Once you have set a GPS Home location, you can create a custom sort to sort your photos by their distance from your GPS Home location. Click on the Sort popup menu in the toolbar and choose the Edit Custom... command. Override one of the ten custom sorts. Then click on the OK button and your new custom distance sort will cause the photos to be sorted by their distance from the current GPS Home location. If you like, you can set one of the three custom thumbnail labels to show the distance. Just enter:

Distance: {distance}

in any one of the Label fields in the Contact Sheet tab of the Preferences dialog and you’ll see the distance each photo’s location is from the current GPS Home location.