GPS Log has several features allowing you to input future destinations, and add/correct previous spike.
Great if you know the lat,lng of a location you want to find (perhaps a geocache?), and for correcting entries where you didn't have the time to wait for a good fix.
If you know the exact latitude and longitude of the location, then you can set these on the spike directly. On a new or existing spike, tap the lat,lng field (below the map), then enter the coords.
These coords can be obtained from another GPS unit, or through searches on Google Maps. But you can also use GPS Log's in-built search to find them which is a lot faster (more below).
GPS Log supports 3 main formats for entering coordinates. The degree symbol (°) can be entered on the iPhone by holding down the zero key. Alternatively, you can use the 'o' character from the regular alphabet. The parser uses fuzzy logic and will try to correct for things like missing degree symbols.
Decimal degrees are the format preferred by Google Maps.
Degrees, Minutes, Seconds
N 51° 3' 42.88", W 1°16' 55.32"
51° 3' 42.88", -1°16' 55.32"
N 51° 3' 42.88", W 1°16' 55.32"
N 22° 31.622 E 113° 59.852 (geocaching.com format) S37° 56.679' E145° 10.141' (geocaching.com.au format)
OS Grid References (British)
GPS Log supports British National Grid References.
OS Grid coordinates are assumed to to use the OSGB36 datum, and are automatically converted to the WGS84 datum.
SU 50410 29420
SU 50 29
SU 5029 // NB. without a space, the number of digits must be an even number! This equals SU 50 29
IMPORTANT NOTE: This transform use a Helmert transform which introduces a ±7m error. Please do not rely on this calculation for critical tasks.
Aside: if you find yourself wanting to convert to and from OS grid references frequently, then try out other App OS Grid Converter
Coordinates in OSGB36
GPS Log (and the iPhone hardware, and Google Maps, and most international systems) uses WGS84. If you need to import a OSGB36 unit it is important to convert it first.
GPS Log will accept an OSGB36 coordinate in either the Decimal Degrees or Degrees, Minutes, Seconds format, but it must be prefixed with OSGB: (including the colon). Examples:
OSGB: N 51° 3' 40.92", W 1°16' 50.07" // equals N 51° 3' 42.88", W 1°16' 55.32" in WGS84
OSGB: 51.061368, -1.280575 // equals 51.061912, -1.282033 in WGS84
This prefix is not required for coordinates using OS Grid References, as OSGB36 is assumed.
IMPORTANT NOTE: OSGB transforms use a Helmert transform which introduce a ±7m error. Please do not rely on this calculation for critical tasks. I you find yourself wanting to convert to and from OSGB36 frequently, then try out other App OS Grid Converter
Correcting Existing Entries
If you have an spike with a missing or inaccurate fix there two easy options to correct it. Open the map for the spike by tapping on the mini-map.
1. If you can see where the location should be, simply drag the pin from it's current position to where it should be. Alternatively you can drop a pin at the desired location (by long-tapping the map), then set the Spike to this location from its callout.
2. Or you can do a search for your position. If the current position is within a few kilometers of the actual location, you can do location specific searches like "starbucks" or "airport". If you have no position recorded, you may need to enter a more complete address containing your city and country (e.g. "JFK Airport, New York"). If the search returns a result that is correct, simply tap the pin, press the call-out arrow, and pick "Use as Spike's Location".
Adding Manual Entries
If you want to add a new spike for a particular location, you can either create a new spike and follow the steps for 'Correcting Existing Entries', or create them directly from the map. Creating directly from the map has the advantage that they will be pre-populated with the name and address of the location you searched.
From the main GPS Log screen, simply hit the 'Map' toolbar icon. Now use the search feature to find the locations you wish to add. Tap the search result pin, select the call-out arrow and select 'Add spike for location'.
Alternatively (since GPS Log 3.1), you can drop a pin on the map where you want the spike by long-tapping on the area. Once the pin has dropped, tap the pin, select the call-out arrow and select 'Add spike for location'.
You can now edit the title and description, add tags, notes and photos, just like with a normal spike. To add existing photos, you first need to sync the photos onto your iPhone so they appear in the Photos app. Then, in the spike select 'Add new photo', and tap 'Choose Existing'.
You can also set the date. Do this by tapping on the visit date. Note that by default, GPS Log shows a date picker wheel which is highly useful for picking times within about 4 weeks of the current date, but not very suitable for entering dates that are long ago, or far in the future. To facilitate that, in GPS Log -> Settings -> Advanced Settings, under 'Display', turn 'Manual timestamp editing' to ON.
Manually created entries are treated the same as ones that use a GPS fix. The only difference is that the accuracy is displayed as 'manual' to indicate that you added this position manually. On export, GPS Log will report the accuracy for manual entries as 0m (i.e. highly accurate).