A noteworthy geotagging application is HoudahGeo by Houdah Software. It has an extraordinarily tidy user interface that comfortably leads you through the three main steps of geotagging: picking images, merging geodata and creating output files. But is ist just tidy on the outside? We tested the latest version HoudahGeo 2.2.5, released only yesterday.
See my “Test Scenario” post.
HoudahGeo’s preference pane offers some useful options that you may want to activate prior to start working with it. Namely, support for iPhoto and other libraries and very handy presets for manual geotagging.
Putting HoudahGeo at the beginning of any imaging workflow is a good idea, and is also the procedure recommended by Houdah Software. (This is specifically important if you are using iPhoto!)
A typical session with HoudahGeo requires very little help from the manual as the interface is pretty tidy with clear tool tips and contextual hints.
We first walk through our log-based workflow, merging images with a track log. The following end-to-end workflow took less than two minutes: load images, indicate timezone, load track log, check result and save output files.
As defined in our test scenario, we load CR2 images from a folder on our harddisk using the “add images from files” button of the red section.
On import, we choose the timezone of the camera’s internal clock when the images were taken. Remember that the timezone indicator for the same location changes when DST rules! With your clock set to the ruling local time, add one hour during summer, e.g. GMT+2 instead of GMT+1, and vice versa. You may also pick your regional timezone indicator from the dropdown, such as “Europe/London”: in this case DST is automatically observed (if the camera was set correctly). If your camera was not set to local time I recommend you run the Automator action described in my timezones post first.
In the second line of HoudahGeo’s dialog, time deviation in minutes may be entered if the camera’s clock is fast or slow. Don’t worry if you are not sure about this: you may always get back to this dialog later in the workflow.
Please keep in mind that this step concerns the camera only, not the track log file! GPS units take their time from satellites – their track logs do not have to be corrected.
Step 2: Merging Geodata (Yellow Section)
In order to merge the files with our locally stored GPX log, we use the “load GPS data from file” icon in the yellow area. HoudahGeo automatically matches images to coordinates if possible.
There are generally two possibilities why an image may appear at the wrong location: either the camera’s time zone and deviation were not set correctly and all images are off their original location by some degree. Or an individual image fell victim of a weak satellite reception at the time.
The first problem can be solved by setting the camera’s time and deviation from the “Images >> Camera Setup” menu, i.e. correcting the values entered on import. The second problem can be solved by re-positioning the pin in either of the “Geocoding” dialogs (third and fourth icon in the yellow area). We will explain how to do this in the “Manual Workflow” section below.
Optionally, more location data can be retrieved through the “Reverse Geocoding” dialog. The latest version of HoudahGeo also fetches altitude values.
Step 3: Creating Output Files (Green Section)
Now, with all geodata retrieved for our image set, HoudahGeo offers various export options: save metadata, export to Google Earth (KMZ) or KML, Flickr or Locr. We follow our test scenario and save the metadata tags (see below for metadata integrity and KML/KMZ export).
A choice of sensible options meets different archiving needs: “always write XMP sidecar” leaves the image files untouched, but adds an XMP file, “create copies” preserves the content of the source directory. If you check “Timestamp”, timezone offset is added to the EXIF data and GPS date/time values are created (recommended if you did not run my timezone script before). If you leave the “artist” option checked, the name of the current MacOS user is entered into the corresponding field.
Manual geotagging is your choice if you either do not have a GPS unit or track log, or if coordinates from a log-based workflow were off to some degree due to bad satellite reception.
HoudahGeo offers two possibilities to geotag images manually, either through Google Maps or Google Earth. Both have their specific advantages: while Google Maps is faster at startup and lets you quickly switch between three alternative map views, Google Earth can be used offline in a limited way (location must be in cache beforehand). According to Pierre Bernard from Houdah Software, HoudahGeo is currently tested for future support of other mapping providers.
The Google Maps dialog is very tidy and shows the familiar toolbars and options. If you enabled “automatically proceed to next image” in the preferences pane, your workload is reduced to a minimalistic two clicks per image. Conveniently, the dialog also includes a bookmarking feature to quickly jump to your favourite locations.
The fourth button of HoudahGeo’s yellow toolbar section launches Google Earth and a geotagging panel. With preferences set to “automatically proceed to next image” and the terrain layer activated it is marginally more efficient than its sibling, because altitude values are automatically added. In my tests, altitude values were determined more reliably here than through the “Reverse Geocoding” dialog were results seem to be heavily interpolated.
If you use either of both dialogs to correct already tagged images, the map will automatically center to the image’s location. This makes re-tagging really fast. Conveniently, any number of highlighted images from the same spot can be tagged in one go.
Houdah Software have done their homework thoroughly: when writing metadata, all existing entries stay untouched while new values are entered correctly. This is probably due to the fact that they wisely put Phil Harvey’s ExifTool at the core of their metadata engine (just as they integrated GPSBabel for direct link-up to GPS units).
I did a few runs with various file types – geotagged and untagged DNG and CR2 files – and got issues only in a rather improbable constellation where different values were used in CR2 files and the corresponding fields of their XMP sidecars (Lightroom always only uses XMP sidecars for CR2 metadata).
Creating map-based slideshows or publishing maps with images online is usually done with the help of the Keyhole Markup Language (KML). This is a XML standard, meaning it is represented by a simple text file with instructions and links. The markup language is not complicated, but with a larger number of images and individual formatting ideas it just gets to large to type it out.
HoudahGeo offers support for KML/KMZ output, the latter hidden under the “Export to Google Earth” button. The difference between the two formats is marginal, as KMZ is basically a ZIP archive containing a KML folder structure, i.e. XML file and related images. Both KML and KMZ can be used in Google Earth and online maps.
A sample KMZ file to view in Google Earth can be downloaded from here (ca. 400 KB).
HoudahGeo creates both output types in an acceptable form, but the export options are highly limited. Except for the preview size users cannot influence the layout in which the images are displayed, nor can they choose which metadata shows up.
According to Pierre Bernard, there are plans to provide greater flexibility and formatting options in a future version of HoudahGeo.
Conclusion: Smoothness and Reliability
HoudahGeo gets full score under the scrutiny of our Nine Requirements: showing an amazing swiftness and ease of use it creates standards-compliant geotagged images, offering sensible alternative approaches to meet individual preferences. With the top rating in terms of smoothness and reliability, HoudahGeo is the geotagging reference other applications have to be measured against.
Needless to say that HoudahGeo is well worth the $30 price tag.
Test Results Overview
See my introductory post for more details on the Nine Requirements.
- All posts in “Geotagging” category
- Geotagging and the Mac (1) – Basics
- Geotagging and the Mac (2) – Test Scenario
- Geotagging and the Mac (3) – iPhoto ’09 “Places”
- Geotagging and the Mac (5) – Google Picasa
- April 23rd, 2009: updated “Step 1″ section (alternative timezone setting), added rating plate
- May 8th, 2009: added note that Google Earth’s altitude values seem to be more reliable