user4222: I have a problem to combine both code for Arduino GSM Shield and Adafruit Ultime GPS Shield. I already change my code to the basic one like examples. I think i found the problem. The problem is when i want to do get request to the url/web.
Here is the link to the Adafruit Ultimate GPS Shield.
Adafruit Library
Adafruit Ultimate GPS Shield Info
My code base on example of Arduino GSM Library (GSM Web Client) and Adafruit GPS Library (Parsing)
This is the code that make my code not working. If i put the code i do not receive any data at serial.

 // if you get a connection, report back via serial:
 if (client.connect(server, port))
 {
    Serial.println("connected");
   // Make a HTTP request:
   client.print("GET ");
   client.print(path);
   client.println(" HTTP/1.1");
   client.print("Host: ");
   client.println(server);
   client.println("Connection: close");
   client.println();
 } 
 else
 {
  // if you didn't get a connection to the server:
  Serial.println("connection failed");
 }

This is the basic code that working so far

// ********************************************
//   GPS Library
// ********************************************
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
#include <stdlib.h>


// ********************************************
//   GSM Library
// ********************************************
#include <GSM.h>


// ********************************************
//   Sim Card Pin Number if available
// ********************************************
#define PINNUMBER ""


// ********************************************
//   Set Up APN data for GPRS Connection
// ********************************************
#define GPRS_APN       "Maxis" // replace your GPRS APN
#define GPRS_LOGIN     "maxis"    // replace with your GPRS login
#define GPRS_PASSWORD  "wap" // replace with your GPRS password


// ********************************************
//   Initialize GSM Library
// ********************************************
GSMClient client;
GPRS gprs;
GSM gsmAccess; 

// ********************************************
//   Setup Arduino to browse URL/web through GPRS
//   The code below will setup path like:
//   http://arella.com.my/urltomysql.php?firstname=Muhammad&lastname=Faiz
//   When Arduino browse the web, it will submit firstname:Muhammad
//   and lastname:Faiz into database. I want to store GPS data into database       later
// ********************************************
char server[] = "arella.com.my";
char path[] = "/urltomysql.php?firstname=Muhammad&lastname=Faiz";
int port = 80; // port 80 is the default for HTTP


// ********************************************
//  Set Adafruit GPS to use software serial on pin 
//  D9 & D10 on Arduino. Use Jumper Wire from D7,D8 to D9,D10
// ********************************************
SoftwareSerial mySerial(10, 9);
Adafruit_GPS GPS(&mySerial);


// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences. 
#define GPSECHO  false

// this keeps track of whether we're using the interrupt
// off by default!
boolean usingInterrupt = false;
void useInterrupt(boolean); // Func prototype keeps Arduino 0023 happy


//***********************************************
// convert NMEA GPS Format to Google Map Format
//***********************************************
int degLatInt, degLongInt;
float minLatFloat, minLongFloat, googleMapsLat, googleMapsLong;
char* lat_str = new char[10];
char* long_str = new char[10];
char degLatString[5], degLongString[5];


void setup()  
{ 
   Serial.begin(115200);
   gsmAccess.begin(PINNUMBER);
   gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD);

   boolean notConnected = true;
   while(notConnected)
   {
      if((gsmAccess.begin(PINNUMBER)==GSM_READY) &
         (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD)==GPRS_READY))
         notConnected = false;
      else
      {
         Serial.println("Not connected");
         delay(1000);
      }
   }
   // If i enable the code below, my code not working.
   /* if (client.connect(server, port))
      {
      Serial.println("connected");
      // Make a HTTP request:
      client.print("GET ");
      client.print(path);
      client.println(" HTTP/1.1");
      client.print("Host: ");
      client.println(server);
      client.println("Connection: close");
      client.println();
  } */


 //***********************************************
 // Setup Adafruit GPS Shield
 //***********************************************
 // connect at 115200 so we can read the GPS fast enough and echo without  dropping chars
 // also spit it out

 Serial.println("Adafruit GPS library basic test!");

 // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
 GPS.begin(9600);

 // uncomment this line to turn on RMC (recommended minimum) and GGA (fix     data) including altitude
 GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
 // uncomment this line to turn on only the "minimum recommended" data
 //GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
 // For parsing data, we don't suggest using anything but either RMC only or RMC+GGA since
 // the parser doesn't care about other sentences at this time

 // Set the update rate
 GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ);   // 1 Hz update rate
 // For the parsing code to work nicely and have time to sort thru the data, and
 // print it out we don't suggest using anything higher than 1 Hz

 // Request updates on antenna status, comment out to keep quiet
 GPS.sendCommand(PGCMD_ANTENNA);

 // the nice thing about this code is you can have a timer0 interrupt go off
 // every 1 millisecond, and read data from the GPS for you. that makes the
 // loop code a heck of a lot easier!
 useInterrupt(true);

   delay(1000);
}

// Interrupt is called once a millisecond, looks for any new GPS data, and stores it
SIGNAL(TIMER0_COMPA_vect) {
   char c = GPS.read();
   // if you want to debug, this is a good time to do it!
   #ifdef UDR0
   if (GPSECHO)
   if (c) UDR0 = c;  
   // writing direct to UDR0 is much much faster than Serial.print 
   // but only one character can be written at a time. 
   #endif
}

void useInterrupt(boolean v) {
   if (v) 
   {
      // Timer0 is already used for millis() - we'll just interrupt somewhere
      // in the middle and call the "Compare A" function above
      OCR0A = 0xAF;
      TIMSK0 |= _BV(OCIE0A);
      usingInterrupt = true;
   } else 
   {
      // do not call the interrupt function COMPA anymore
      TIMSK0 &= ~_BV(OCIE0A);
      usingInterrupt = false;
   }
}

uint32_t timer = millis();

void loop()                     // run over and over again
{
   // if a sentence is received, we can check the checksum, parse it...
   if (GPS.newNMEAreceived()) {
   // a tricky thing here is if we print the NMEA sentence, or data
   // we end up not listening and catching other sentences! 
   // so be very wary if using OUTPUT_ALLDATA and trytng to print out data
   //Serial.println(GPS.lastNMEA());   // this also sets the newNMEAreceived()  flag to false

   if (!GPS.parse(GPS.lastNMEA()))   // this also sets the newNMEAreceived() flag  to false
      return;  // we can fail to parse a sentence in which case we should just wait for another
   }

   // if millis() or timer wraps around, we'll just reset it
   if (timer > millis())  timer = millis();
   // approximately every 2 seconds or so, print out the current stats
   if (millis() - timer > 5000) { 
      timer = millis(); // reset the timer

      Serial.print("\nTime: ");
      Serial.print(GPS.hour+8, DEC); Serial.print(':');
      Serial.print(GPS.minute, DEC); Serial.print(':');
      Serial.print(GPS.seconds, DEC); Serial.print('.');
      Serial.println(GPS.milliseconds);
      Serial.print("Date: ");
      Serial.print(GPS.day, DEC); Serial.print('/');
      Serial.print(GPS.month, DEC); Serial.print("/20");
      Serial.println(GPS.year, DEC);
      Serial.print("Fix: "); Serial.print((int)GPS.fix);
      Serial.print(" quality: "); Serial.println((int)GPS.fixquality); 
      if (GPS.fix) {  
         /////////// Latitude /////////////
         // Convert NMEA Latitude to String
         dtostrf(GPS.latitude, 7, 4, lat_str); //convert GPS.latitude from float to String. 7 - means 8 characters long ; 4 - means 4 decimal point 

         // Get Degree substring from latitude String
        strncpy(degLatString, lat_str, 1); // Get Degree from Full Latitude String. Example 311.7799 - Get 3

        // Get Minutes substring from latitude String
        char* minLatString = lat_str + 1; // Move pointer up 1 position. Example 311.7799 will move to 11.7799

        // Convert Deg String to int
        degLatInt = atoi(degLatString);

        // COnvert Min String to float
        minLatFloat = atof(minLatString);

        //Convert NMEA latitude to Google Maps latitude
        googleMapsLat = degLatInt + (minLatFloat / 60); 
        Serial.print("Google Map Latitude: ");
        Serial.println(googleMapsLat, 4);

        //////////// Longitude /////////////
        // Convert NMEA Longitude to String
        dtostrf(GPS.longitude, 8, 4, long_str); //convert GPS.latitude from float to String. 8 - means 9 characters long ; 4 - means 4 decimal point 

        // Get Degree substring from latitude String
        strncpy(degLongString, long_str, 3); // Get Degree from Full Latitude String. Example 10141.91699 - Get 141

        // Get Minutes substring from latitude String
        char* minLongString = long_str + 3; // Move pointer up 3 position. Example 10141.9169 will move to 41.7799

        // Convert Deg String to int
        degLongInt = atoi(degLongString);

        // COnvert Min String to float
        minLongFloat = atof(minLongString);

        //Convert NMEA latitude to Google Maps latitude
        googleMapsLong = degLongInt + (minLongFloat / 60); 
        Serial.print("Google Map Longitude: ");
        Serial.println(googleMapsLong, 4);

        Serial.print("Speed (KM): "); Serial.println(GPS.speed * 1.85);
      }
   }
}


user4933: I'm working on the same project (with the same hardware) and I have an identical problem.
Seems like an HTTP request blows up your serial monitor, but is not true in my view. 
In fact, if you use the TinyGPS++ library will not have this problem anymore.
Take as reference the GsmWebClient example, you can add a few lines of code.
This is all you need for parse with tinyGPS:
#include <AltSoftSerial.h>

#include <TinyGPS++.h>

TinyGPSPlus gps;

AltSoftSerial ss;

//Add this to your sketch, in loop() or setup()

ss.begin(9600);

while (ss.available() > 0)

    if (gps.encode(ss.read())) {
        gps.location.lat(); //return latitude as a double
        gps.location.lng(); //return longitude as a double
}


4222: <p>I have a problem to combine both code for Arduino GSM Shield and Adafruit Ultime GPS Shield. I already change my code to the basic one like examples. I think i found the problem. The problem is when i want to do get request to the url/web.</p>

<p><strong>Here is the link to the Adafruit Ultimate GPS Shield.</strong>
<a href="https://github.com/adafruit/Adafruit-GPS-Library" rel="nofollow noreferrer">Adafruit Library</a>
<a href="https://learn.adafruit.com/adafruit-ultimate-gps-logger-shield" rel="nofollow noreferrer">Adafruit Ultimate GPS Shield Info</a></p>

<p>My code base on example of Arduino GSM Library (GSM Web Client) and Adafruit GPS Library (Parsing)</p>

<p><strong>This is the code that make my code not working. If i put the code i do not receive any data at serial.</strong></p>

<p><img src="https://i.stack.imgur.com/DhQqd.png" alt="Blank Data at serial"></p>

<pre><code> // if you get a connection, report back via serial:
 if (client.connect(server, port))
 {
    Serial.println("connected");
   // Make a HTTP request:
   client.print("GET ");
   client.print(path);
   client.println(" HTTP/1.1");
   client.print("Host: ");
   client.println(server);
   client.println("Connection: close");
   client.println();
 } 
 else
 {
  // if you didn't get a connection to the server:
  Serial.println("connection failed");
 }
</code></pre>

<p><strong>This is the basic code that working so far</strong></p>

<p><img src="https://i.stack.imgur.com/ngvU7.png" alt="Working Code"></p>

<pre><code>// ********************************************
//   GPS Library
// ********************************************
#include &lt;Adafruit_GPS.h&gt;
#include &lt;SoftwareSerial.h&gt;
#include &lt;stdlib.h&gt;


// ********************************************
//   GSM Library
// ********************************************
#include &lt;GSM.h&gt;


// ********************************************
//   Sim Card Pin Number if available
// ********************************************
#define PINNUMBER ""


// ********************************************
//   Set Up APN data for GPRS Connection
// ********************************************
#define GPRS_APN       "Maxis" // replace your GPRS APN
#define GPRS_LOGIN     "maxis"    // replace with your GPRS login
#define GPRS_PASSWORD  "wap" // replace with your GPRS password


// ********************************************
//   Initialize GSM Library
// ********************************************
GSMClient client;
GPRS gprs;
GSM gsmAccess; 

// ********************************************
//   Setup Arduino to browse URL/web through GPRS
//   The code below will setup path like:
//   http://arella.com.my/urltomysql.php?firstname=Muhammad&amp;lastname=Faiz
//   When Arduino browse the web, it will submit firstname:Muhammad
//   and lastname:Faiz into database. I want to store GPS data into database       later
// ********************************************
char server[] = "arella.com.my";
char path[] = "/urltomysql.php?firstname=Muhammad&amp;lastname=Faiz";
int port = 80; // port 80 is the default for HTTP


// ********************************************
//  Set Adafruit GPS to use software serial on pin 
//  D9 &amp; D10 on Arduino. Use Jumper Wire from D7,D8 to D9,D10
// ********************************************
SoftwareSerial mySerial(10, 9);
Adafruit_GPS GPS(&amp;mySerial);


// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences. 
#define GPSECHO  false

// this keeps track of whether we're using the interrupt
// off by default!
boolean usingInterrupt = false;
void useInterrupt(boolean); // Func prototype keeps Arduino 0023 happy


//***********************************************
// convert NMEA GPS Format to Google Map Format
//***********************************************
int degLatInt, degLongInt;
float minLatFloat, minLongFloat, googleMapsLat, googleMapsLong;
char* lat_str = new char[10];
char* long_str = new char[10];
char degLatString[5], degLongString[5];


void setup()  
{ 
   Serial.begin(115200);
   gsmAccess.begin(PINNUMBER);
   gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD);

   boolean notConnected = true;
   while(notConnected)
   {
      if((gsmAccess.begin(PINNUMBER)==GSM_READY) &amp;
         (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD)==GPRS_READY))
         notConnected = false;
      else
      {
         Serial.println("Not connected");
         delay(1000);
      }
   }
   // If i enable the code below, my code not working.
   /* if (client.connect(server, port))
      {
      Serial.println("connected");
      // Make a HTTP request:
      client.print("GET ");
      client.print(path);
      client.println(" HTTP/1.1");
      client.print("Host: ");
      client.println(server);
      client.println("Connection: close");
      client.println();
  } */


 //***********************************************
 // Setup Adafruit GPS Shield
 //***********************************************
 // connect at 115200 so we can read the GPS fast enough and echo without  dropping chars
 // also spit it out

 Serial.println("Adafruit GPS library basic test!");

 // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
 GPS.begin(9600);

 // uncomment this line to turn on RMC (recommended minimum) and GGA (fix     data) including altitude
 GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
 // uncomment this line to turn on only the "minimum recommended" data
 //GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
 // For parsing data, we don't suggest using anything but either RMC only or RMC+GGA since
 // the parser doesn't care about other sentences at this time

 // Set the update rate
 GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ);   // 1 Hz update rate
 // For the parsing code to work nicely and have time to sort thru the data, and
 // print it out we don't suggest using anything higher than 1 Hz

 // Request updates on antenna status, comment out to keep quiet
 GPS.sendCommand(PGCMD_ANTENNA);

 // the nice thing about this code is you can have a timer0 interrupt go off
 // every 1 millisecond, and read data from the GPS for you. that makes the
 // loop code a heck of a lot easier!
 useInterrupt(true);

   delay(1000);
}

// Interrupt is called once a millisecond, looks for any new GPS data, and stores it
SIGNAL(TIMER0_COMPA_vect) {
   char c = GPS.read();
   // if you want to debug, this is a good time to do it!
   #ifdef UDR0
   if (GPSECHO)
   if (c) UDR0 = c;  
   // writing direct to UDR0 is much much faster than Serial.print 
   // but only one character can be written at a time. 
   #endif
}

void useInterrupt(boolean v) {
   if (v) 
   {
      // Timer0 is already used for millis() - we'll just interrupt somewhere
      // in the middle and call the "Compare A" function above
      OCR0A = 0xAF;
      TIMSK0 |= _BV(OCIE0A);
      usingInterrupt = true;
   } else 
   {
      // do not call the interrupt function COMPA anymore
      TIMSK0 &amp;= ~_BV(OCIE0A);
      usingInterrupt = false;
   }
}

uint32_t timer = millis();

void loop()                     // run over and over again
{
   // if a sentence is received, we can check the checksum, parse it...
   if (GPS.newNMEAreceived()) {
   // a tricky thing here is if we print the NMEA sentence, or data
   // we end up not listening and catching other sentences! 
   // so be very wary if using OUTPUT_ALLDATA and trytng to print out data
   //Serial.println(GPS.lastNMEA());   // this also sets the newNMEAreceived()  flag to false

   if (!GPS.parse(GPS.lastNMEA()))   // this also sets the newNMEAreceived() flag  to false
      return;  // we can fail to parse a sentence in which case we should just wait for another
   }

   // if millis() or timer wraps around, we'll just reset it
   if (timer &gt; millis())  timer = millis();
   // approximately every 2 seconds or so, print out the current stats
   if (millis() - timer &gt; 5000) { 
      timer = millis(); // reset the timer

      Serial.print("\nTime: ");
      Serial.print(GPS.hour+8, DEC); Serial.print(':');
      Serial.print(GPS.minute, DEC); Serial.print(':');
      Serial.print(GPS.seconds, DEC); Serial.print('.');
      Serial.println(GPS.milliseconds);
      Serial.print("Date: ");
      Serial.print(GPS.day, DEC); Serial.print('/');
      Serial.print(GPS.month, DEC); Serial.print("/20");
      Serial.println(GPS.year, DEC);
      Serial.print("Fix: "); Serial.print((int)GPS.fix);
      Serial.print(" quality: "); Serial.println((int)GPS.fixquality); 
      if (GPS.fix) {  
         /////////// Latitude /////////////
         // Convert NMEA Latitude to String
         dtostrf(GPS.latitude, 7, 4, lat_str); //convert GPS.latitude from float to String. 7 - means 8 characters long ; 4 - means 4 decimal point 

         // Get Degree substring from latitude String
        strncpy(degLatString, lat_str, 1); // Get Degree from Full Latitude String. Example 311.7799 - Get 3

        // Get Minutes substring from latitude String
        char* minLatString = lat_str + 1; // Move pointer up 1 position. Example 311.7799 will move to 11.7799

        // Convert Deg String to int
        degLatInt = atoi(degLatString);

        // COnvert Min String to float
        minLatFloat = atof(minLatString);

        //Convert NMEA latitude to Google Maps latitude
        googleMapsLat = degLatInt + (minLatFloat / 60); 
        Serial.print("Google Map Latitude: ");
        Serial.println(googleMapsLat, 4);

        //////////// Longitude /////////////
        // Convert NMEA Longitude to String
        dtostrf(GPS.longitude, 8, 4, long_str); //convert GPS.latitude from float to String. 8 - means 9 characters long ; 4 - means 4 decimal point 

        // Get Degree substring from latitude String
        strncpy(degLongString, long_str, 3); // Get Degree from Full Latitude String. Example 10141.91699 - Get 141

        // Get Minutes substring from latitude String
        char* minLongString = long_str + 3; // Move pointer up 3 position. Example 10141.9169 will move to 41.7799

        // Convert Deg String to int
        degLongInt = atoi(degLongString);

        // COnvert Min String to float
        minLongFloat = atof(minLongString);

        //Convert NMEA latitude to Google Maps latitude
        googleMapsLong = degLongInt + (minLongFloat / 60); 
        Serial.print("Google Map Longitude: ");
        Serial.println(googleMapsLong, 4);

        Serial.print("Speed (KM): "); Serial.println(GPS.speed * 1.85);
      }
   }
}
</code></pre>
 4933: <p>I'm working on the same project (with the same hardware) and I have an identical problem.
Seems like an HTTP request blows up your serial monitor, but is not true in my view. 
In fact, if you use the TinyGPS++ library will not have this problem anymore.
Take as reference the GsmWebClient example, you can add a few lines of code.</p>

<p>This is all you need for parse with tinyGPS:</p>

<pre><code>#include &lt;AltSoftSerial.h&gt;

#include &lt;TinyGPS++.h&gt;

TinyGPSPlus gps;

AltSoftSerial ss;

//Add this to your sketch, in loop() or setup()

ss.begin(9600);

while (ss.available() &gt; 0)

    if (gps.encode(ss.read())) {
        gps.location.lat(); //return latitude as a double
        gps.location.lng(); //return longitude as a double
}
</code></pre>
