The GPS sample App

This sample app demonstrates the usage of the GNSS service along with a few other services and APIs to find nearby points of interest using reverse-geocoding, along with their distances. It also allows for finding the current location in the form of a physical address.

It uses the following internal services and APIs:

GNSS service with .adef bindings and related .cdef requires, provides, and sources sections.
le_dcs Interface and c_le_net services with .adef bindings and related .cdef requires, provides, and sources sections.
JSON Parsing API, a Legato JSON parser to interpret the response from MapBox.
Dynamic Memory Allocation API, a Legato memory management API.
Event Loop API, an API for event-driven programming in Legato.
Thread Control API, a Legato thread control API.

As well as the following external libraries and APIs:

cURL, a library for transferring data with URLs.
MapBox, a 3rd-party API that performs geocoding on coordinates.

The gpsApp is a sample application exposing the above services and APIs and demonstrating their usage as well as how they can work together to solve a real world problem. This sample app provides two executables, one for the service and another one for the controller. You can find:

An .adef file:
- gpsApp.adef to define the executables, processes, requires, bindings, and externals.
An .sdef file:
- gpsApp.sdef to define the commands, and the system structure
Two .cdef files:
- Component.cdef for the service component
- Component.cdef for the controller

Note: The app is built along with a complete system using the .sdef in order to use the command line tools to control the application.

Go to the sample code.

Install the sample app:

$ cd apps/sample/gpsApp
$ make wp76xx
$ app install gpsApp.wp76xx.update <ip address>

where ip address is the address of your target device.

If you're not using a Sierra Wireless WP76xx module, replace wp76xx with the appropriate identifier for your target.

Note: The gpsApp has only been tested on WP76xx.

Usage

To use the app to find your current location, use the following command :

map locate

Note

An optional accuracy option can be set to fine-tune the level of accuracy to which an address is generated. For example, the following command only tries to locate to within 30 meters of accuracy.

map -a 30 locate

To use the app to find points of interest, use the following command :

map find <Name of POI>

Note

Accuracy can be set using the same method as above. A boundary box can also be set to only search within a box. For example, the following command can be used to find a cafe to within a distance of 5 KMs. Accuracy will also be set to 5 meters.

map -a 5 -w 5 find cafe

For more information on specific commands, read the following section taken from the app's help.

        "NAME\n"
        "        map - perform GNSS/positioning operations such as finding nearby places using forward geocoding.\n"
        "\n"
        "Prerequisites\n"
        "        A MapBox Access Token is needed for all operations.\n"
        "        A GNSS receiver as well as data connection are required as well.\n"
        "\n"
        "SYNOPSIS\n"
        "        map [OPTION]... COMMAND [Place Name]\n"
        "        map -h\n"
        "        map --help\n"
        "\n"
        "COMMANDS\n"
        "       find\n"
        "               Searches for <Place Name> in the proximity of the current coordinates provided by the GNSS\n"
        "                service and fed into the mapbox api.\n"
        "\n"
        "       locate\n"
        "               Get the current coordinates using the GNSS service, and feed them into mapbox's reverse-\n"
        "                geocoding api to turn the coordinates into an address.\n"
        "\n"
        "OPTIONS\n"
        "       -w N\n"
        "       --within=N\n"
        "               Confine the search to within an imaginary square with sides 2*N KM and your current\n"
        "                coordinates are at the center of the square. The provided N KMs will be converted\n"
        "                to coordinates and fed into the mapbox api.\n"
        "               If not specified, the current coordinates will be used and results will be found,\n"
        "                within the proximity of the current location.\n"
        "       -a N\n"
        "       --accuracy=N\n"
        "               This is the accuracy in meters to which the device will be located. In other words,\n"
        "                if the accuracy reaches 20m the algorithm will not try to further the accuracy and use\n"
        "                the available coordinates.\n"
        "               If not specified, it will be set to 20 meters by default.\n"