Geotagging photo's on non-GPS Camera

[BobvdMeij]

Hello all,

Does anyone have experience with geotagging their photo's that were captured using a camera without embedded GPS? We are planning on purchasing a Sony A7R for aerial photogrammetry, but are still looking for ways to provide the images with GPS tags. The tags do not need to be highly accurate in an absolute sense. Relative positioning between photo's should do to significantly lower processing time.

Geotagging through matching time stamps of individual images and a GPS track should get us a long way, but it seems we will not be able to export the flight logs from our upcoming UAV to do just that. Likewise, there seem to be many GPS logging/tagging systems available that were specifically designed for Canon and Nikon camera's, but Sony has not released any such a system. Hence we may need to look for external devices, such as GPS trackers/ loggers/ etc.

We came across this interesting product thus far, but find the price relatively high considering that of similar systems for other camera brands. I have not yet been able to locate other systems that integrate well with the Sony, for example through it's hotshoe on the top. Alternatively, we are considering more consumergrade devices such as this 'GPS Laptimer' that should be capable of continuously logging positional data at up to 10 times a seconds. Due to its lightweight it can be easily mounted on our UAV during flights, and both battery and storage capacity should get us through a project quiet well.

Obviously then, it seems we will inevitably require some sort of (non-ideal) workaround and spend some time on post-processing of the camera + positional data afterwards to provide geotags. I am looking for experiences out there with similar setups? What device(s) are you using, how do they perform? What software do you use for post-processing of geotags afterwards? Are there other options we may consider worthwhile to look at as well?

Thanks in advance!

[Packy_GIS]

Well - I have this GeoSnad tool mounted on my IR camera and it works quite well - but yes, the price is very high.
 I have done such geotaging using the onboard Garmin GPX that is mounted in our aircraft and it is not difficult.
Just mount any of the cheep (and small) tracking devices (or sport watch with GPS)  and log your track into a GPX file.
You have to synchronize the camera time with the GPS time - you can do this together with geotaging your images:
1. Take a picture of your GPS showing the precise time with the camera you use (if the track logger has a display)
2. Look at the picture and check the EXIF and compute the time difference
3. Use a software the will apply the time shift and will add the GPS coordinates from the GPX file (based on the corrected time)

I have tried several softwares and the best that work for is Zoner - check google for the workflow

Good luck.

Jan

[BobvdMeij]

Well - I have this GeoSnad tool mounted on my IR camera and it works quite well - but yes, the price is very high.
 I have done such geotaging using the onboard Garmin GPX that is mounted in our aircraft and it is not difficult.
Just mount any of the cheep (and small) tracking devices (or sport watch with GPS)  and log your track into a GPX file.
You have to synchronize the camera time with the GPS time - you can do this together with geotaging your images:
1. Take a picture of your GPS showing the precise time with the camera you use (if the track logger has a display)
2. Look at the picture and check the EXIF and compute the time difference
3. Use a software the will apply the time shift and will add the GPS coordinates from the GPX file (based on the corrected time)

I have tried several softwares and the best that work for is Zoner - check google for the workflow

Good luck.

Jan

Hello Jan,

Great to have actually found someone who has experience using the Geosnap module, are you using the Express or Pro (inc. IMU) module? I reckon we will eventually opt for a similar device, although we may pospone that to a moment later in time as the remainder of our rig has been paid for through projects. Until then, I am afraid a 'simple' but relatively high frequency (10Hz +) GPS logger and some post-process-geotagging will do.

Could you perhaps elaborate a bit more on the Geosnap module, how it works and how it fits within your workflow in a userfriendly manner? Do you trigger the camera using the module itself (by time or distance, for example), or do you use an external trigger (Time Lapse mode, mission planning app, etc.) for that and only use the Geosnap to record the position?

If using the Trigger by Distance on the Geosnap; how accurate is it? Or, does it deliver the precise spacing interval between images as you set it? I am a bit reluctant on that matter considering its a basic GPS system and I would rather not sacrifice my overlap.

Considering the geotagging, how does that precisely work? Does it immediately write the position data to the JPEG's EXIF file, or do you still require some post-processing. Also, does this geotagging only work when using the Geosnap for the triggering? Or would it also be possible for the Geosnap to 'read' when a trigger is initiated (through external means) and still write the position data after all?

Other than that, thanks for your input once again! I will certainly have a look at the Geosnap later on, unless some cheaper alternative/ Sony propietary solution has been released by then, and make good use of your tips and tricks!

Bob

[Packy_GIS]

Hi Bob.
We have to Pro version including the IMU unit.  We bought it about 3 years ago for about 6000€ (paid from a project).

We have it mounted on a Tetracam ADC Lite camera and it is somehow connected directly to the camera body and it's electornics. This means that camera is set to auto-trigger (every 2 seconds) and the images are stored to the camera's SD card. The GeoSnap has it's own SD card where is stored the corresponding image name together with the GPS and IMU information.

Processing is very easy as I only load the images into PS and import the GPS and IMU data in the reference pane and here we go. The accuracy is not very good (we are talking about meters) but I use it in the mountains, where signalizing and measuring GCP would be very time consuming  and regarding the resolution and the usage of the IR images I found this satisfying.

I can send you some sample data, if you are interested.

Jan

[BobvdMeij]

If you would be willing to do so that would be great, much appreciated! It is hard to wrap your head around things based on some informatory webpage/ marketing flyer only !

So if I am correct, the Geosnap does not actually alter the EXIF/Details of the images on the camera (Tetracam in your case) itself, but rather a seperate .csv/.txt file with the image name (which it then somehow is capable of retrieving from the camera) and appropiate position/attitude data?

Still wondering you align the two in Photoscan though. I haven't come across a button in the Add Photos dialog or in the Reference pane to combine the image and position data with one another.

[Packy_GIS]

Hi,
data are available here
Password is in PM.
In PS look in the Reference pane for icon "Import" (Table with a folder icon).

I have a tool called Geotility - and this is used for fast georeferencing (not ortorectifiction) of images obtained from Geosnap tool. It uses Google as basemap and it should be free (I don't remember). This tool can visualize the whole flight from a track file (that I have as well included in the sample data).

Jan

[TXPE]

I've used both Mission Planner and Geosetter to geotag images from non-GPS cameras.

I don't know exactly how they are doing it, but Event38 is using the Reach Emlid with the Sony QX-1 as a PPK solution.  The Pixhawk tells the camera to take the photo based on distance and the Reach logs the when and where the photo is actually taken based on a hot shoe type connection to camera.  RTKpost is used to generate a file with the coordinates for each photo that can be loaded into PS (not directly geotagging the images).  This workflow is easier, faster, and more accurate than MP or Geosetter.

Doug

[mobilexcopter]

Hello all,

we have a simmilar device  GPS Logger for logging trigger position based on different events. With hotshoe adapter that works with Sony and other cameras you can log positions based on camera trigger positions to microSD card and then use the logs as desired. With optional imu module you can also store direction in log files if needed. Basicaly works the same as solution mentioned at top.

Best regards,

Alex

[BobvdMeij]

Hello all,

we have a simmilar device  GPS Logger for logging trigger position based on different events. With hotshoe adapter that works with Sony and other cameras you can log positions based on camera trigger positions to microSD card and then use the logs as desired. With optional imu module you can also store direction in log files if needed. Basicaly works the same as solution mentioned at top.

Best regards,

Alex

Thanks! That appearrs to be a very interesting option, particularly considering its A LOT cheaper compared to FOV's GeoSnap Express module. You have indeed confirmed it should work with Sony camera's, such as the A7R series?

As for the IMU is concerned, this is a very welcome addition! Unfortunately I cannot find any information on pricing of the module including an IMU. Any clue on that?

[mobilexcopter]

Hello,

yes, we can confirm that it works with A7R series and other newer Sony cameras like A6xxx, A5xxx range.

IMU module can be added with check mark on the right pane (  there is also a price for IMU add-on ).

We will add a video of logger in action, hopefully record it this weekend.

Best regards,

Alex

 

[JMR]

We also have a solution but in our case it goes a bit further because we use dual frequency (L1/L2) gnss on board and a ground based station to allow differential corrections by means of post processing (aka PPK). we can use regular survey grade GNSS receivers as base as well as available CORS rinex data.
We supply a software tool for solving camera positions that takes into account camera mount offset and dual IMU recordings, one fixed to the aircraft frame and another one built in the hot shoe shutter sensor thus fixed to the camera body. In this way we can make kinematic offset corrections for articulated camera setups.
We have proven camera positions can be cm accurate making unnecessary the use of ground control points.
The system can send trig signals on it own at given distance/time interval, but is compatible with trigger commands sent by your current setup. in fact you can let them go directly to the camera or log them bypassing the signal through our board. The actual shutter actuation is grabbed from the hotshoe and logged with milisecond accurate time stamp.
Our system works well with any camera with flash port or hotshoe, and of course works flawlessly with A7
if you are interested, please feel free to send mail.
www.drobit.es

[SAV]

Hi JMR,

Sounds like a great system you have developed there. What price range are we talking about?

Regards
SAV

[Packy_GIS]

Yes - this looks really interesting.
I have contacted their support - so I am awaiting "the good news"
Jan

[mobilexcopter]

Thanks! That appearrs to be a very interesting option, particularly considering its A LOT cheaper compared to FOV's GeoSnap Express module. You have indeed confirmed it should work with Sony camera's, such as the A7R series?

As for the IMU is concerned, this is a very welcome addition! Unfortunately I cannot find any information on pricing of the module including an IMU. Any clue on that?

Hello,

we added a short video of our logger in action and transfer of information to EXIF. It's a bit wobbly, but shows the feature in question.

If you would be using Pixhawk controller, you can achieve the same thing with an hotshoe adapter and a setting or two. 

Best regards,

Alex