To use PicLocata, first download the file PicLocata-1-5.exe and run it to install the program on your PC. The installation file supports Windows XP, Vista and Windows 7.
Piclocata works with any GPS that is capable of recording a track and saving it in GPX format (see below). It has been tested with:
Differences between your camera's clock and the GPS time will cause errors in the picture position. Many cameras allow the clock to be set only to the nearest minute. However they record the time of each picture to the nearest second.
Fortunately, there is an easy way to correct for differences in time. When you go out, switch your GPS to a screen that shows the current time, and then take a picture of the GPS with your camera. PicLocata provides a way to use that picture later to correct for time differences.
You may need to change a setting on your GPS to see the time. On my eTrex Legend:
PicLocata works with any digital cameras that records the time when a picture is taken. As far as I know, that is all digital cameras.
The main requirements are that you keep your GPS switched on while taking pictures, and that it maintains a good signal during this time. My GPS works well if I keep it in the lid of by rucsac, or clipped to the rucsac strap in front of my folder. It should also be fine hung round your neck, and it is easy to check the signal at intervals that way.
My GPS didn't work as well kept in my hip pocket, and there were occasional large errors in the track. Note that recent eTrex models have a high-sensitivity receiver that may work better than my older model.
No GPS works effectively indoors, so PicLocata is really just for outdoor photography. However it can handle short breaks in the GPS signal, such as when you might stand under a bridge to take a picture.
When you have finished, upload your pictures to your PC. Put the pictures in a single folder until you have processed them with PicLocata.
This version of PicLocata requires a GPS track in GPX format (GPS eXchange Format). Future versions may support other formats; contact me if you need something different.
To save the track from a Garmin GPS:
If you have another make of GPS, or if you don't have MapSource, TopoGrafix EasyGPS is free and works well.
It's convenient to save the track in the same folder as your pictures, but this isn't essential.
After you have uploaded the track, I recommend you reset the current track in your GPS. Some models may reduce the accuracy of the track if it becomes too long, and I have seen one case where GPS locked up occasionally, and the problem seemed to be cured by resetting the track after a few days use.
Run PicLocata, for example by Start - All Programs - PicLocata. The program shows a single window where you perform all the main functions. There are just four steps to follow.
There are five ways to save location data, and you may use any, or all, of them at the same time:
P1050573.JPGmight be renamed to
P1050573 NN 6687 6461.JPG.
A GPS track consists of a set of points and times. Generally each picture will be taken part way between two points, and PicLocata estimates position along a line joing the points by assuming the photographer moved at a steady speed between them. This isn't necessarily the case, and so the process introduces a small uncertainty in the position.
However in testing I found that, at walking pace, track points were usually close together. Consequently PicLocata shouldn't introduce an error of more than 5m in the position, which is little worse than the inherent inaccuracy of a consumer grade GPS. Matching test pictures against Google Maps satellite pictures confirmed that the PicLocata position was often more accurate that this.
By default, PicLocata will refuse to set the location of a picture if it is more than 20m from the nearest track point. In practice few pictures taken while walking have failed this test unless the GPS signal was poor. The limit is configurable, and might need to be changed if taking pictures using a cycle, boat, etc.
If you take pictures with more than one camera on a trip:
PicLocata will retain the synchronisation data for each camera, and show how long it has been since you last synchronised that camera. If you stop using a camera, press the corresponding "X" button to remove it from the list.
PicLocata can read and process the following raw image formats:
Raw files can be renamed and sorted into grid square folders, just like JPEG files. However PicLocata does not attempt to modify the EXIF data in raw files.
PicLocata can also handle unrecognised raw files when if your camera is set to record "Raw + JPEG". Any file with the same name as a JPEG, including raw files and sidecar XMP files can be renamed and and sorted into a gridsquare folder.
Processing of raw images is configurable; see Options below.
PicLocata was originally written with Geograph in mind. If you append the picture location to the file name, the Geograph V2 submission process will pick up the location automatically. Similarly, Geograph will automatically pick up the location from the picture's EXIF data.
Geograph uses the location on the file name as the subject position, and the location in EXIF data as the photographer's position.
(There is a minor unavoidable difference between the two methods. The picture name specifies a position with 10m accuracy. The EXIF data specifies a precise GRS80 lat/lon position which Geograph converts to a grid point.)
I find it convenient to sort my pictures into grid squares before submitting them. This allows me to choose the best ones for each square, and check for unnecessary duplications of existing Geograph pictures.
Setting the location in EXIF data works well with Picasa. Picasa can show the picture location in a Google Maps satellite image. In Picasa select "View / Places" and then choose "Satellite" or "Hybrid" in the window on the right. I found this is often helpful in confirming the accuracy of the location and the direction of view.
The "Tools / Options" menu allows these changes:
|Coordinate System||OSGB (for Great Britain).|
Irish Transverse Mercator (the new system for Republic of Ireland and Northern Ireland).
Irish Grid (the older system for Ireland).
|Maximum distance from nearest track point||Pictures that are too far from a track point will not be assigned a location. The default value is 20m.|
|Maximum break in track with no signal||PicLocata ignores short breaks in the GPS signal, such as occur when stopping under a bridge, and will assign locations to pictures taken at these points. The default value is 10m; set it to zero to stop breaks from being ignored.|
|Saved Picture Locations||Select eight-figure grid references (10 metre resolution) or ten-figure grid references (1 metre resolution).|
|Number of Cameras in Use||Select 2, 3 or 4 if you use multiple cameras during a day. PicLocata will allow you to set separate synchronisation times for each camera.|
|Process all image types||Reads time information from supported raw files, as well as JPEG files. (Enabled by default.)|
|Rename with JPEG||When a JPEG file is renamed to include a grid reference, renames any associated raw or XMP files. (Disabled by default.)|
|Move with JPEG||When a JPEG file is moved to a grid square sub-folder, moves any associated raw or XMP files. (Disabled by default.)|