GPS datalogging problem.

Hi!
I am new to arduino programming so please forgive me if this question is stupid. I am trying to store GPS altitude data along with the data from an ultrasonic sensor. I can program the sensor without issue so I didn’t include that into the code. My problem is that it outputs 0 : 0.00 : 0 when it should say something like 0 : 180.7 : 57. I just have seconds in there because I need to have a real time clock as well. I deleted a bunch of GPS things from the example that I didn’t think were necessary in order to fit under the memory limit of the Uno.
Code:

#include <SPI.h>
#include <SD.h>
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
#include <NewPing.h>
SoftwareSerial mySerial(8, 7);
Adafruit_GPS GPS(&mySerial);
#define GPSECHO true
#define TRIGGER_PIN 12
#define ECHO_PIN 11
#define MAX_DISTANCE 200
int total;
int pin;
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
const int chipSelect = 10;
void setup()
{

Serial.begin(115200);
Serial.println(“Adafruit GPS library basic test!”);

GPS.begin(9600);

GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);

GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ); // 1 Hz update rate

GPS.sendCommand(PGCMD_ANTENNA);

pinMode(10, OUTPUT);
SD.begin(chipSelect);
delay(1000);
mySerial.println(PMTK_Q_RELEASE);
}

SIGNAL(TIMER0_COMPA_vect) {
char c = GPS.read();
}

void loop()
{
char c = GPS.read();
File dataFile = SD.open(“datalog.txt”, FILE_WRITE);
dataFile.print(total);
dataFile.print(" : “);
dataFile.print(GPS.altitude);
dataFile.print(” : ");
dataFile.println(GPS.seconds, DEC);
/dataFile.print(now.hour());
dataFile.print(".");
dataFile.print(now.minute());
dataFile.print(".");
dataFile.println(now.second());
/
dataFile.close();

}

Any help would be greatly appreciated!

I deleted a bunch of GPS things from the example that I didn't think were necessary in order to fit under the memory limit of the Uno.

But, you are still reading data in loop() AND in an ISR... Stop doing one of them. (Probably the ISR).

You'll need to post a link to the Adafruit_GPS library.

You will probably need to put the stuff back that you deleted, too. What you thought was not necessary probably is.

The way you are reading data now is wrong.