Survey: Nikon geotaggers
Recent Nikon DSLRs has built-in support for automatically attaching positioning metadata to an image if fitted with on-camera GPS receiver. This survey discusses the dedicated GPS receivers from Nikon and from third party sources.
Some cameras such as the Sony SLT-A77 or Nikon Coolpix P510 comes with a built-in GPS chip that provides position metadata based upon the World Geodetic System 1984 (WGS 84), Nikon DSLRs require you to attach an external unit to accomplish the same thing. I am not going to speculate on why Nikon has left this feature out of its best cameras, but just notice that fitting a compatible GPS receiver to a Nikon DSLR that supports GPS, will allow you to automatically record location metadata with the images. This means that the traditional way of geotagging photos, which involves using a separate GPS device to record way-points in a log-file that is merged into an image file by software, is no longer necessary.
Currently, there are two alternatives to capture GPS data directly in a Nikon camera. The first is to connect a generic GPS device via the Nikon MC-35 GPS Adapter Cord to the 10-pin socket on the camera. Nikon certifies portable devices from Garmin and Magellan to be used with the MC-35. The second is to use the Nikon GP-1 and compatible dedicated GPS receiver connected directly to the camera.
If you already own a compatible Garmin or Magellan device, you may want to consider the first alternative. But these devices are expensive when purchased brand new along with the MC-35, and the serial interface is rather bulky. In this survey, we shall look at the Nikon GP-1 and some alternative units that can replace it as dedicated Nikon geotaggers.
The WGS 84 system picks up latitude, longitude, altitude and UTC time from a number of satellites (currently 20) that orbits the earth. All GP-1 compatible devices communicate these four data points to a compatible camera, which then stores them as EXIF metadata.
In addition, some of the more sophisticated devices contains a two-axis or three-axis compass that produces heading data that records in the image EXIF metadata the direction the camera lens was pointed when the photograph was taken. Unlike the four other data points, the heading data is not derived from GPS satellites, but from a built-in magnetometer that reacts to the earths magnetic field. A two-axis compass only provide reliable data when the camera is level, while a three-axis compass is supposed to work no matter what angle you hold the camera. Note that the Nikon D200 does not record heading data in EXIF.
Some units have on-board memory that can be used to generate continuous logs of way-point data. These units often let you extract other metadata such as speed, pitch and tilt. These data are computed from way-point data and cannot be embedded in images, since there are no EXIF fields defined for them. You can download the log of way-points to a computer and use it to plot your entire itinerary (not only the points along the way were you took photographs) on a map. Way-point logs can also be used, along with appropriate software, to synchronise location data to any photograph with an embedded time-stamp.
Nikon GP-1 and compatible units
Nikon GP-1 uses the GP-CA10 cable to transmit the data to Nikon D200, D300, D300s, D700, D800, D800E, D2-series, D3-series and D4-series bodies through the 10-pin connector; and the GP1-CA90 cable to transmit the data to the Nikon D3100, D3200, D5000, D5100, D7000, and D90. It can also be connected to a PC with an USB cable. Since the units occupies the 10-pin port, the Nikon remote shutter release MC-DC2 (for the D90) can be plugged into a second port on the GP-1 if you need to use a wired remote release at the same time.
Three manufacturers, Columbus, Promote and YongNuo makes units that have very similar specifications to the Nikon GP-1. The build quality and quality control of the cheapest of these third party units may not be as good as the Nikon unit (so you risk having to return a dud to have it replaced under warranty), but otherwise, these third products sit in the camera's accessory shoe and work just like the Nikon GP-1.
Search for Nikon GP-1 and similar products for sale at known outlets (the price indicated is typical, prices tend to vary over time):
- Nikon GP-1 (USD 200): Adorama, Amazon USA, Amazon UK, B&H, eBay.
- Columbus nGPS (USD 108): eBay.
- Macsense Geomet'r (USD 90): Adorama, Amazon USA, B&H, eBay.
- Opteka GPN-1 (USB 50): Amazon USA, Amazon UK, eBay.
- Phottix GP-1 (USB 169): eBay.
- Promote N-1 (USD 149): Adorama, Amazon USA, B&H, eBay.
- YongNuo N-918 (USD 79): eBay.
- Search for any GPS: Adorama, Amazon USA, Amazon UK, B&H, eBay.
All the units listed above are bare-bones GPS devices. You can see the real-time GPS data by looking at the camera LCD rear screen, and they record latitude, longitude, altitude and time information and automatically embeds this in the EXIF metadata of pictures taken with a compatible Nikon camera.
None of these devices come with a battery. Power is supplied from the camera body as long as the camera is turned on. If you keep the camera turned on all day to keep the GPS unit locked on satellites, you may run out of power. The Nikon D3, D700, D800, D800E, D300, D90 and D7000 let you set Setup menu → GPS → Auto meter off. This reduces the drain on the battery but may prevent GPS data from being recorded if you forget to allow time (about 45 seconds after half-press) for the receiver to again acquire data from enough satellites.
Dawn di-GPS receivers
The di-GPS brand receivers are manufactured and sold by Dawn Technology Ltd. in Hong Kong. Four different models are currently available.
- di-GPS M3 MTK (USD 120).
- di-GPS M3 L (USD 152).
- di-GPS M3 DC (USD 165).
- di-GPS Pro L (USD 255).
The basic model, di-GPS M3 MTK, has a feature set similar to the Nikon GP-1. The di-GPS M3 L also has a data-logger. The di-GPS M3 DC also has a 3-axis compass (but no data-logger). The di-GPS Pro L is protected against dust and moisture, and features a Nikon 10-pin plug on top for attaching a remote release. It has a data-logger (but no compass).
The built quality of the di-GPS models are excellent. And while most models that attach to the Nikon 10-plug with a cable uses a plug that sticks out like a sore thumb, Dawn di-GPS Pro L has a design where the plug is angled inwards, towards the body. This is a very nice detail.
Dawn also supplies a software utility (di-GPS-2map) to work with the data-logger files extracted via an USB-port to visualise GPS data.
Solmeta GPS receivers
However, powering the GPS receiver by the camera's battery may put quite a strain on your camera’s battery life. Also if the receiver is powered down completely to save power, it will require up to six minutes to lock on GPS data from a satellite.
Solmeta makes four different GPS receivers that are compatible with the Nikon GP-1. Three of them improves on the design of GP-1 by having their own built in internal rechargeable battery, lasting up to 10 hours. They will only switch over to Nikon camera for power source when the internal battery is drained. The Solmeta N3 does not have its own battery, but its design is optimised for low power consumption.
Search for Solmeta GPS receivers (the price indicated is typical, prices tend to vary over time):
- Solmeta N1 (USD 99): eBay.
- Solmeta N2 (USD 145): eBay.
- Solmeta N3 (USD 189): eBay.
- Solmeta Pro 2 (USD 289): eBay.
Like the other Solmeta models, the most advanced unit from Solmeta, the Solmeta Geotagger Pro 2 will automatically tag images taken with a compatible Nikon camera with standard GPS data (latitude, longitude, altitude, UTC time and heading). This data is also displayed on the unit's LCD, and my be periodically recorded as way-points in a file which is stored in its 2 Gbyte internal memory. The LCD may also used to display speed, pitch and tilt. These numbers are computed from way-point data and not used for tagging. To convert the Solmeta Geotagger Pro 2 data to the standard format for use with other software, use the free program GPSbabel and select «NMEA 0183 sentences» as input and «GPX XML» format as output.
Since the device occupies the 10-pin port, the N1, N2 and N3 receivers comes with a wired remote shutter release included. The Pro 2 receiver does not, but it has a built-in 2.4 GHz wireless receiver that works with an optional wireless shutter release. The Pro 2 may also be used as an interval timer.
MetaGPS GPS receivers
MetaGPS also offers a choice of GPS receivers.
Search for MetaGPS receivers (the price indicated is typical, prices tend to vary over time):
- MetaGPS M0 (USD 118): Amazon USA, eBay.
- MetaGPS M1 (USD 128): Amazon USA, eBay.
- MetaGPS M2 (USD 168): Amazon USA, eBay.
The MetaGPS M0 model have similar specifications to the Nikon GP-1, the M1 model features and internal battery, and the M2 model features and internal battery and a 2-axis compass that provides heading data. However, the manual does not explain how to calibrate the compass, and according to some user reports, the compass does not work reliably without calibration.
When you connect a Nikon GP-1 or compatible GPS receiver to the camera with the appropriate cord, and turn the camera on, the GPS icon (shown right) will be displayed on the camera's LCD display, provided the GPS receiver is able to get position data from three or more satellites. If no signal is received from the unit for more than two seconds, the GPS icon will no longer be displayed in the control panel and no GPS data will be recorded.
When the GPS receiver is active, taking a photo will automatically record the GPS data as part of the photo's EXIF metadata.
To view the GPS data, select Setup menu → GPS → Position in the camera's setup menu on a compatible Nikon DSLR. The current latitude, longitude, altitude, universal time (UTC), and heading will be displayed on the camera's LCD. Note that the (UTC) received from the GPS satellite is recorded separately from the time-stamp provided by the camera clock. (This menu option is not available with D2X, D2XS, D2HS, and D200 cameras.)
Some of the units come with a USB socket and software that allow you to connect the unit to a laptop or tablet instead of a camera. You can use this as an alternative means for recording GPS data.
The table below gives an overview of all the GPS receivers discussed in this survey. The data (except price) has been compiled from the manufacturer's data sheets.
All devices listed below record latitude, longitude, altitude and UTC time. Only the devices with a compass recording heading.
|Nikon GP-1||Columbus nGPS||Macsense Geomet'r||Phottix GP-1||Promote N-1||YongNuo N-918|
|Chip||Unknown||MTK||SiRF III||SiRF III||SiRF III||SiRF III|
|Indoors||No data||No data||No data||No data||Last||No data|
|di-GPS Pro L|
|Chip||Unknown||MTK||SiRF III||SiRF III||SiRF III|
|Logger||No||No||8 Mbyte||No||8 Mbyte|
|Solmeta N1||Solmeta N2||Solmeta|
|Solmeta Pro 2|
|Compass||No||2 axis||3 axis||3 axis|
|MetaGPS M0||MetaGPS M1||MetaGPS M2|
|Chip||SiRF III||SiRF III||SiRF III|
|Indoors||No data||No data||No data|
Price is based on best price (excluding shipping) listed on eBay or manufacturer's home page in June 2011. Note that prices vary over time, and the prices listed are just an indicator of what you should expect to pay for an item.
Chip indicates what GPS chip the receiver uses. Most of devices use the SiRF Star III chip (20 tracking channels). However, the Columbus nGPS, di-GPS M3-MTK, Solmeta N2, Solmeta N3 and Solmeta Pro 2 uses the MTK MT3329 (aka. MTK v2) chip (66 searching, 22 tracking channels). Both chips have a good reputation for accuracy, but the MTK MT3329 is supposed to consume less power, be more sensitive, and provide a faster fix than the older SiRF Star III.
The “Indoors” column indicates what data the unit supply when it is indoors or otherwise out of reach from GPS satellites. Last indicates that it then reports the last position available (typically just outside the building). This is of course not correct, but if the unit does not keep a way-point log, having access to last position is (IMHO) better than having No data.