6.6.4 MathOperations

MathOperations performs mathematical calculations based on a source location and a target location.

The following is an example for using MathOperations:

Distance_measured = location_handle.call('MathOperations', {'MathRequest': u'FindDistance', 'DistanceParamSource': {'Longitude': u'10', 'Latitude': u'15', 'Altitude': u'20'}, 'DistanceParamDestination': {'Longitude': u'40', 'Latitude': u'55', 'Altitude': u'20'}})

The following table summarizes the specification of MathOperations:

Interface	`ILocation`
Description	Performs mathematical calculations based on a source location and a target location.
Response Model	Synchronous
Pre-condition	Device must be Location aware (that is, it must have some location service provider in form of GPS, AGPS, or Bluetooth). ILocation interface loaded.
Post-condition	Nil

Input Parameters

Input parameter specifies the mathematical operation such as FindDistance, FindBearingTo and so on, and position co-ordinates for performing the mathematical operation.

Name	Type	Range	Description
`MathRequest`	string	`FindDistance` `FindBearingTo` `MoveCoordinates`	Specifies the mathematical operation.
`DistanceParamSource`	map. For more information, refer table map- `Distance Param Source` 6.137	NA	This specifies the position co-ordinates. Note that expected datum here is WGS-84 with decimal degree representation. Also note that altitude supplied does not effect the result of calculation. It is used to maintain a uniform input argument, which makes it easy to use.
`DistanceParamDestination`	map. For more information, refer table map- `Distance Param Destination` 6.138	NA	Specifies co-ordinates of another position. It is not required when value specified in the first parameter is `MoveCoordinates`. Note that expected datum here is WGS-84 with decimal degree representation.
`MoveByThisDistance` (only if `MathRequestType` is `MoveCoordinates`)	double	NA	Move source position by the specified the distance.
(Only if `MathRequestType` is `MoveCoordinates`)	double	NA	Move the source position by the specified bearing.

Table 6.137: map- DistanceParamSource

Key	Type	Description
Longitude	double	Longitude data
Latitude	double	Latitude data
Altitude	double	Altitude data

Table 6.138: map- DistanceParamDestination

Key	Type	Description
Longitude	double	Longitude data
Latitude	double	Latitude data
Altitude	double	Altitude data

Output Parameters

Output parameter contains ReturnValue. It also contains ErrorCode, and ErrorMessage if the operation fails.

Name	Type	Range (Type: string)	Description
`ReturnValue`	The table 6.140 describes output obtained for various input combination	NA	Resultant calculation. In case you request to `Move coordinates`, map described in column 2 will be returned. Note that if distance between two coordinate is requested, it is returned in meters while `FindBearingTo` returned is in degrees counting clockwise relative to true north.
`ErrorCode`	int	NA	Service specific error code on failure of the operation.
`ErrorMessage`	string	NA	Error description in Engineering English.

MathRequest type in input	Obtained output type	Description
`FindDistance`	double	Contains the calculated distance in meters.
`FindBearingTo`	double	Bearing between two points.
`MoveCoordinates` map	Map described in the table 6.141 is returned, which represents the translated coordinate.

Table 6.141: map- MoveCoordinates

Key	Type	Description
Longitude	double	Longitude data
Latitude	double	Latitude data
Altitude	double	Altitude data

Errors

The following table lists the error codes and their values:

Error code value	Description
`1002`	Bad argument type

Error Messages

The following table lists the error messages and their description:

Error messages	Description
`Location:MathOperations:Missing argument- MathRequest`	Indicates missing `Mathrequest` argument.
`Location:MathOperations:Wrong argument- MathRequest`	Indicates supplied `MathRequest` argument is wrong.
`Location:MathOperations:Missing argument- locationcoordinate`	Indicates missing `locationCoordinate` in input.
`Location:MathOperations:Missing argument- MoveByThisDistance`	Indicates missing `MoveByThisDistance` in input.
`Location:MathOperations:Missing argument- MoveByThisBearing`	Indicates missing `MoveByThisBearing` in input.
`Location:MathOperations:TypeMismatch- MoveByThisDistance`	Indicates type for `Movebydistance` is wrong.
`Location:MathOperations:TypeMismatch- MoveByThisBearing`	Indicates type for `Movebythisbearing` is wrong.

Example

The following sample code illustrates how to perform specific calculations on user provided data:

import scriptext
location_handle = scriptext.load('Service.location', 'ILocation')

try:
    Distance_measured = location_handle.call('MathOperations', {'MathRequest': u'FindDistance', 'DistanceParamSource': {'Longitude': u'10', 'Latitude': u'15', 'Altitude': u'20'}, 'DistanceParamDestination': {'Longitude': u'40', 'Latitude': u'55', 'Altitude': u'20'}})
    errorcode = Distance_measured["ErrorCode"]
    if errorcode != 0:
        print "Error in retrieving the Distance covered"
    else:
        ret_val = Distance_measured["ReturnValue"]
        if ret_val["distance covered"]["Value"] == '50':
            print "The distance covered is  retrieved"

except scriptext.ScriptextError, err:
    print "Error performing the operation : ", err

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