Posts Tagged ‘geotagging’
Thanks to digiKam’s geocorrelation capabilities, you can geotag photos using a GPX file created with apps like Open GPS Tracker. But there is also another way to use your Android device for geotagging. The built-in camera app of most Android devices is capable of geotagging photos. This means that you can take a geotagged snap with the Android camera and then transfer geographical coordinates from it to other photos using digiKam. So next time, when you are done shooting with your main camera, remember to take a reference snapshot with your Android device (make sure that the geotagging option is enabled).
In digiKam, select the reference snapshot along with the photos you want to geotag and choose Image → Geo-location. Right-click on the reference snapshot in the selection list and choose Copy coordinates. Mark then the rest of the photos in the list, right-click on the selection, choose Paste coordinates, press the Apply button, and you are done.
Need to quickly geotag a bunch of photos taken at a specific location? ExifTool is your friend. Using this powerful command-line tool, you can geotag multiple photos with a single command. Before you proceed, make sure that ExifTool is installed on your machine. To install ExifTool on Ubuntu, execute the sudo apt-get install libimage-exiftool-perl command. Next, you have to obtain the longitude and latitude of the desired geographical location, and feed the coordinates to ExifTool as follows:
exiftool -GPSLongitudeRef=E -GPSLongitude=139.7513889 -GPSLatitudeRef=N -GPSLatitude=35.685 *.jpg
This command will geotag all JPEG images in the current directory. If you are running Windows, download the latest version of the ExifTool executable and rename it as in the example below:
exiftool (-GPSLongitudeRef=E -GPSLongitude=139.7513889 -GPSLatitudeRef=N -GPSLatitude=35.685).exe
Drag and drop the photos you want to geotag onto the executable and ExifTools will do the rest. Besides GPSLongitudeRef, GPSLongitude, GPSLatitudeRef, and GPSLatitude, ExifTools supports a number of other tags. Check the GPS Tags page for further info.
Geolocation is not a new feature, but in digiKam 2.0 it has been thoroughly reworked to streamline the process of geotagging photos. The new Geolocation interface (Image » Geo-location) aggregates all geotagging tools in one place. The interface itself consists of three parts: the map pane contains a map and a toolbar with several navigation tools; below the map pane, there is a list of selected photos; the sidebar on the right displays the currently active section.
To geotag photos, you need to obtain the geographical coordinates of the place where the photos were taken, and the Geolocation interface offers several ways to do that. For starters, you can use the mouse to move around the map to locate the desired spot. By default, the Geolocation interface uses the OpenStreetMap service as its map source, but you can switch to Google Maps using the Maps Settings button below the map pane. If you know the full or partial address of the location, you can use the built-in search feature to find it on the map. Click on the Search tab, enter the address in the search field, hit the Search button, and you should see a list of matching results with corresponding pins on the map.
The easiest way to add geographical coordinates to the photos is to drag them from the list onto the desired spot on the map. Alternatively, you can assign the geographical coordinates of a specific search result to the photos. To do this, select the photos in the list, right-click on the desired search result, and pick the Move selected images to this position item from the context menu.
If you regularly take photos in a specific location, you can create a bookmark for it in the Geolocation interface. To do this, right-click on the desired location on the map, choose Add Bookmark, give the bookmark a name, and provide an optional description. To keep tabs on your bookmarks, you can group them into folders. To create a new folder, press the Add Folder button in the Add Bookmark dialog window. Select then the created folder from the Folder drop-down list to add the bookmark to it. Press OK to save the bookmark. To assign the bookmarked location to one or several photos, select them in the list, right-click on the selection, and choose the bookmark from the Bookmarks context menu.
Once you’ve assigned the geographical coordinates to the photos, press the Apply button to write geotags to the photos. With digiKam, you can view geotagged on the map without leaving the convenience of your favorite photo management application. Click on the Geolocation sidebar to expand it, select the photo you want, and you should see it on the map.
The Geolocation interface offers another nifty feature called Reverse Geocoding. This tool can retrieve human-readable locations such as city, street, country, etc. for photos based on their geographical coordinates. The obtained location names can be stored in photos as new tags, so you can easily search for photos taken in a specific country, city, or even street.
One way to put this feature to practical use is to create a dedicated Places tag, and then use reverse geocoding to add place-related sub-tags to it. To do this, create a new tag called Places (you can do this in the Tags sidebar). Select then the desired photos and choose Image » Geo-location. If the photos are not already geotagged, assign geographical coordinates to them. Switch then to the Reverse Geocoding section, right-click on the Places tag, and use the available context menu items to add the address elements to the tag (e.g., Country and City). Select all the photos in the list and press the Apply reverse geocoding button. You should see the country and city sub-tags (e.g., Germany and Berlin) under Places. Hit then the Apply button, and you are done. Now you can use the Filter sidebar to quickly locate photos taken in a specific country and city.
You don’t need a fancy camera with a built-in GPS receiver to geotag your photos. An Android device with the Open GPS Tracker app and digiKam can do the job just fine. The app lets you track your route and save it as a GPX file which you can then use to geocorrelate your photos in digiKam.
Geocorrelation is a relatively simple process which assigns geographical coordinates from the GPX file to the photos based on their time stamps. So for this technique to work its magic, you must sync the time on your Android device with your camera. When you head for a photo walk, launch Open GPS Tracker on your Android device and start a new tracking session. When you are back home, stop the tracking session, and use the Share Track button in Open GPS Tracker to save the recorded track in the GPX format on the SD card or send it via email to your machine.
Offload then the photos from your camera to digiKam, select them, and choose Image » Geolocation » Correlator. Press the Load GPX File button and select the GPX file. digiKam should then automatically assign geographical coordinates to the photos. By default, digiKam can tolerate a 30-second gap between the time settings of the camera and the GPX track. If the gap is longer, the application may fail to assign geographical coordinates to some of the photos. In this case, you can increase the time gap in the Max time gap field. Press then the Correlate button to refresh the geographical coordinates. This makes geocorrelation less precise, but you can use the Edit button to adjust the coordinates manually. Once you’re satisfied with the result, press the Apply button to save the assigned coordinates in the photos’ metadata, and you are done.
Need to find all the photos you took in France? You can use the Map Searches sidebar to do just that, provided your photos have been geotagged.
Expand the Map Searches sidebar, press and hold the Ctrl key and select the desired region on the map using the mouse. You should then see markers on the map. Each marker displays the number of found photos in the specific location, and you can use the mouse or zoom buttons to zoom in on the map to see thumbnails of the found photos. You can also see all found photos in the main pane. If you press and hold the Shift key and then click on a marker on the map, digiKam will highlight all the photos belonging to this group in the main pane.
digiKam also allows you to save map searches. This way, you don’t have to perform the same map search every time you need to find photos in a specific region. Enter a name for your search in the field below the map and hit the Save button. This adds the search to the My Map Searches section, and you can activate the saved search at any time by clicking on it.
By the way, digiKam supports both Marble and OpenStreetMap maps, so you can use the map you like for viewing the found photos in the Map Searches sidebar. You can switch between the Marble and OpenStreetMap maps using the Map Settings button.
Thanks to Gilles Caulier for the tip.
Even if your camera doesn’t support geotagging, you can easily add geographical coordinates to your photos using digiKam.
In digiKam, select the photo you want to geotag and choose Image -> Geolocation -> Edit Coordinates. This opens the Edit Geographical Coordinates window containing a map. Drag the map with the mouse and zoom on a specific area to locate the exact place where the photo was taken. Alternatively, you can use the Search field to enter the address, for example: botanic garden, berlin, germany. Hit then the Search button, and you should see a list of found places that are marked with pins on the map. To add geographical coordinates to the photo, click on the exact spot on the map to add a pin to the place where the photo was taken. You can then drag the pin with the mouse to adjust the pin’s position. Hit then OK, and you are done.
If you use a GPS device to record your track when shooting photos, you can use digiKam’s Correlator tool to geotag the images (mapping photos using a GPX file is often called geocorrelation). To do this, you have to export the recorded track from your GPS unit as a GPX file. In digiKam, select the photos you want to correlate, choose Image -> Geolocation -> Correlator, then press the Load GPX File button and select the GPX file. Hit then the Correlate button, and digiKam does the rest. Keep in mind that for this feature to work properly, the time on your GPS device and digital camera must be in sync. If the time on both devices differs, you can specify the time gap in the Difference in min[utes] field.
Once you’ve geotagged your photos, you can view them on the map without leaving the convenience of digiKam. To do this, click on the Geolocation sidebar to expand it, select the photo you want, and you should see it on the map. digiKam even lets you choose between different map providers, including Google Maps, OpenStreetMap, and MSN Maps. To switch to the desired map, choose it from the drop-down list at the bottom of the Geolocation sidebar.
- digiKam can geotag photos in the JPEG and RAW formats.
- If your GPS device doesn’t support GPX format, you can use the GPS Babel tool to convert the device’s proprietary format to GPX.
- In the future, digiKam will support Marble and OpenStreetMap for offline geotagging.
- Nokia has recently opened their map web service API, so it’s possible that digiKam will provide support for Nokia maps in the future.
Thanks to Gilles Caulier for the comments.