indication by buzzer for change of latitude and longitude in gps

suppose i'm driving a car at a latitude(+130 7' 7.53" )and longitude(+800 10' 9.92") if i reach the latitude(+138 7' 7.84") and longitude(+850 10' 6.62") i need an buzzer indication....

#include <NewSoftSerial.h>

NewSoftSerial mySerial = NewSoftSerial(2, 3);
#define powerpin 4

//#define GPSRATE 4800
#define GPSRATE 9600

// GPS parser for 406a
#define BUFFSIZ 90 // plenty big
char buffer[BUFFSIZ];
char *parseptr;
char buffidx;
uint8_t hour, minute, second, year, month, date;
uint32_t latitude, longitude;
uint8_t groundspeed, trackangle;
char latdir, longdir;
char status;

void setup()
{
if (powerpin) {
pinMode(powerpin, OUTPUT);
}
pinMode(13, OUTPUT);
Serial.begin(GPSRATE);
mySerial.begin(GPSRATE);

// prints title with ending line break
Serial.println("GPS parser");

digitalWrite(powerpin, LOW); // pull low to turn on!
}

void loop()
{
uint32_t tmp;

Serial.print("\n\rread: ");
readline();

// check if $GPRMC (global positioning fixed data)
if (strncmp(buffer, "$GPRMC",6) == 0) {

// hhmmss time data
parseptr = buffer+7;
tmp = parsedecimal(parseptr);
hour = tmp / 10000;
minute = (tmp / 100) % 100;
second = tmp % 100;

parseptr = strchr(parseptr, ',') + 1;
status = parseptr[0];
parseptr += 2;

// grab latitude & long data
// latitude
latitude = parsedecimal(parseptr);
if (latitude != 0) {
latitude *= 10000;
parseptr = strchr(parseptr, '.')+1;
latitude += parsedecimal(parseptr);
}
parseptr = strchr(parseptr, ',') + 1;
// read latitude N/S data
if (parseptr[0] != ',') {
latdir = parseptr[0];
}

//Serial.println(latdir);

// longitude
parseptr = strchr(parseptr, ',')+1;
longitude = parsedecimal(parseptr);
if (longitude != 0) {
longitude *= 10000;
parseptr = strchr(parseptr, '.')+1;
longitude += parsedecimal(parseptr);
}
parseptr = strchr(parseptr, ',')+1;
// read longitude E/W data
if (parseptr[0] != ',') {
longdir = parseptr[0];
}

// groundspeed
parseptr = strchr(parseptr, ',')+1;
groundspeed = parsedecimal(parseptr);

// track angle
parseptr = strchr(parseptr, ',')+1;
trackangle = parsedecimal(parseptr);

// date
parseptr = strchr(parseptr, ',')+1;
tmp = parsedecimal(parseptr);
date = tmp / 10000;
month = (tmp / 100) % 100;
year = tmp % 100;

Serial.print("\nTime: ");
Serial.print(hour, DEC); Serial.print(':');
Serial.print(minute, DEC); Serial.print(':');
Serial.println(second, DEC);
Serial.print("Date: ");
Serial.print(month, DEC); Serial.print('/');
Serial.print(date, DEC); Serial.print('/');
Serial.println(year, DEC);

Serial.print("Lat: ");
if (latdir == 'N')
Serial.print('+');
else if (latdir == 'S')
Serial.print('-');

Serial.print(latitude/1000000, DEC); Serial.print('\°', BYTE); Serial.print('

');
Serial.print((latitude/10000)%100, DEC); Serial.print('''); Serial.print(' ');
Serial.print((latitude%10000)*6/1000, DEC); Serial.print('.');
Serial.print(((latitude%10000)*6/10)%100, DEC); Serial.println('"');

Serial.print("Long: ");
if (longdir == 'E')
Serial.print('+');
else if (longdir == 'W')
Serial.print('-');
Serial.print(longitude/1000000, DEC); Serial.print('\°', BYTE); Serial.print('

');
Serial.print((longitude/10000)%100, DEC); Serial.print('''); Serial.print('

');
Serial.print((longitude%10000)*6/1000, DEC); Serial.print('.');
Serial.print(((longitude%10000)*6/10)%100, DEC); Serial.println('"');

}
//Serial.println(buffer);
}

uint32_t parsedecimal(char *str) {
uint32_t d = 0;

while (str[0] != 0) {
if ((str[0] > '9') || (str[0] < '0'))
return d;
d *= 10;
d += str[0] - '0';
str++;
}
return d;
}

void readline(void) {
char c;

buffidx = 0; // start at begninning
while (1) {
c=mySerial.read();
if (c == -1)
continue;
Serial.print(c);
if (c == '\n')
continue;
if ((buffidx == BUFFSIZ-1) || (c == '\r')) {
buffer[buffidx] = 0;
return;
}
buffer[buffidx++]= c;
}
}

i need to modify the above program to get the buzzer indication at change of positions i.e.latitude and longitude. please guide me guys

What is the issue? You have a known latitude and longitude that you want to reach. You have a current latitude and longitude. It isn't rocket science to determine is delta latitude and delta longitude are less than some threshold.

not rocket science i need a buzzer sound if the object reaches to that particular longitude and longitude