Settings

Local Logging

This section configures the frequency of recording locations to a local database. There is a switch to enable or disable the service.

Period

This sections allows configuring the time and distance frequency of local logging.

Choose the minimum period between recording locations to the local database. E.g. Choosing 15 seconds ensures locations will not be saved more frequently than every 15 seconds.

Distance

The minimum distance that the device has appeared to travel before a new location will be recorded. A location will not be recorded until the device appears to have moved the specified distance. There is a tolerance of about 10 percent, e.g. if the distance is configured as every 100 metres, if the distance moved is greater than 90 metres it will be recorded.

Setting this value is recommended as it appears to reduce GPS usage. Choose a distance that is appropriate for the speed you are likely to be travelling at and the frequency you wish to log at. E.g. If you are walking at about 4 kph and logging every 10 seconds, a distance of 10 metres would be appropriate.

Before a location will be recorded, both the minimum time and distance parameters must have been exceeded.

Remote Logging

This sections allows the frequency of remote logging in terms of time and distance travelled to be specified. There is a switch to enable or disable the service.

Period

Choose the minimum period between reporting locations to the remote server. E.g. Choosing 10 minutes ensures locations will not be sent more frequently than every 10 minutes.

Whilst the system allows you to choose lower intervals, it is recommended not to use an interval below 3 seconds as when communications are intermittent, a backlog of locations to transmit can build up, which may adversely impact the operation of the system and also put an undue load on the remote server. Even then, for remote logging, once a minute should be sufficiently frequent in most situations.

Distance

Setting this value is recommended as it appears to reduce GPS usage. Choose a distance that is appropriate for the speed you are likely to be travelling at and the frequency you wish to log at. E.g. If you are walking at about 4 kph and logging every 15 minutes, a distance of less than 1 km would be appropriate.

Accuracy

These settings influence the accuracy of locations logged to the remote server. The values chosen also affect battery usage. You configure a combination of;

  • the desired accuracy of the GPS
  • the minimum estimated accuracy or Horizontal Dilution of Precision (HDOP) in metres
  • the maximum time to spend attempting to achieve that level of estimated accuracy

Where fairly frequent location reporting is not required, but a reasonable level of accuracy is desired, the Desired accuracy can be set to 3 kilometres and the Minimum HDOP set to say 30 metres. Wi-Fi and mobile phone networks are then used to ascertain locations and the GPS is turned off. When the app receives a location update that is greater than the Minimum HDOP, the app temporarily changes the Desired accuracy to one that is sufficient based on the Minimum HDOP setting, in this case it would be 10 metres.

The app then monitors location updates received from the GPS up to the maximum time specified by the Seek time period. If a location is received that matches or is better than the Minimum HDOP it will be logged to the remote server. If the Seek time is exceeded the most accurate location is logged to the remote server unless Strict HDOP compliance has been switched on, in which case the location is ignored.

As it is expected that local logging is performed at a much higher level of frequency than remote logging, if Strict HDOP compliance is not enabled and twice the time interval has passed since the last locally recorded location but the minimum HDOP has still not been met, the location will be recorded, except where the specified minimum distance has not been travelled. This is to avoid big gaps in the local track log where GPS coverage may be poor, e.g. in a forest, canyon or building.

If a sufficiently accurate location is achieved within the seek time, it will be recorded. After the seek time has expired, the most accurate location will also be recorded as long as it differs from the most recent.

Desired accuracy

This option influences which hardware is enabled to provide location information.

When the 3 kilometres, 1 kilometre or 100 metres options are chosen, Wi-Fi and the mobile network are used to provide location updates. In this scenario the GPS is not usually turned on, reducing battery usage. Any other options turn on the GPS, increasing battery usage. Using the 10 metres option may use the GPS less frequently than Best and Best for navigation options.

When the Best for navigation option is used, the GPS will be turned on when logging is active and the device potentially uses additional hardware such as the accelerometer and barometer to improve the location accuracy. In order to maintain battery efficiency, it is not recommended to use this option.

It is recommended to use Best for most situations, except where you do not wish to log particularly frequently. E.g. to monitor a long journey by car or train you might using a setting of 1 kilometre or more. If your journey is through built up areas where there are likely to be plenty of Wi-Fi points, setting desired accuracy to 100 metres may prove quite effective.

Minimum HDOP

Horizontal Dilution of Precision (HDOP) is an estimated accuracy in metres that the GPS reports in relation to a location fix.

Accurate Tracks

Experimentation with an iPhone X suggests if you want an accurate track log, most likely when logging locally with a more frequent and detailed track, setting the Minimum HDOP to 15 metres, Desired Accuracy to Best and with a Seek time maximum of 3 minutes produces good results.

Seek time

Specifies the time after which the app gives up looking for a location to match the minimum HDOP.

Strict HDOP compliance

If this switch is turned on, if a location has not been received that matches or is better than the required HDOP value during the seek time period no locations are reported.

If this switch is off, the most accurate location received during the seek time is reported even if it exceeds the minimum HDOP value.

Behaviour

Show activity bar

This feature is only available for devices running iOS 11 or greater.

When switched on, as a reminder, it shows a notification in the status bar of the device when TripLogger is actively monitoring locations and also running in the background. Exactly how this is displayed is a feature of the operating system and varies from device to device. It is recommended to enable this feature as a reminder and only disable it if you find it annoying.

Maximum activity history

The maximum number of events to show in the activity log before clearing the oldest entries.

Should your device report a low-memory condition to the app, the app will clear the log leaving just a few entries to reduce memory usage as much as possible. The log is also cleared when the app is not recording locations and is subsequently closed after a period of idleness.

Remote Host

These settings are quite technical in nature and you are likely to need information from the provider of the remote logging server to set them correctly.

Use HTTPS (secure)

Whether to use HTTP or HTTPS to remotely log locations. For security, this should always be on except in testing environments. Insecure HTTP requests may be blocked by the iOS operating system.

If in doubt, this setting should be on.

Use POST (secure)

Whether locations will be logged to the remote server using the GET or POST HTTP request mechanisms.

The POST mechanism is more secure than GET and should be used if supported by the remote host.

If in doubt, this setting should be on.

JSON body

If this option is enabled, the body of the HTTP POST request will be formatted as a [JSON]() object, otherwise it will be submitted as Form-Data (multipart/form-data mime type).

If in doubt, try with this setting off first. TripServer will accept either format. Form-Data may use slightly less data.

Host address

The Internet address of the host handling remote location logging. This can be either a name or an IP address. Only enter the name or IP address. Don’t prefix it with the protocol (e.g. HTTP or HTTPS). e.g. just www.example.com not https://www.example.com/.

Host port

A numeric value indicating a port address.

This should normally be blank and only needs specifying if the remote server is using a non-standard value. When blank, the system will automatically use the standard values of port 80 for HTTP and port 443 for HTTPS.

Host path

For use with TripServer, normally this must be set to /trip/rest/log_point.

User identifier

A value provided by the remote logging service to uniquely identify you to the remote system.