Arduino NEO M8N gps that writes data to SD card

GPS_NEO_M8N_SD.c

//      GPS
//      TX   - Pin 8 - green
//      RX   - Pin 9 - yellow
//
//      SD card attached to SPI bus as follows:
//      MOSI - Pin 11
//      MISO - Pin 12
//      CLK  - Pin 13

//      CS   - Pin 10
//

#include <NMEAGPS.h>
#include <GPSport.h>
#include <SD.h> //Load SD card library
#include <SPI.h> //Load SPI Library
//
//#define RX_PIN 8
//#define TX_PIN 9

NMEAGPS  gps;
gps_fix  fix;

int pinCS = 10; // CS pin of the SD card
File file;

void setup()
{
  DEBUG_PORT.begin(9600);
  while (!Serial)
    ;

  pinMode(pinCS, OUTPUT); // pin mode for SD Card reader


  if (SD.begin()) {
    DEBUG_PORT.println("SD card ready to use.");
  } else {
    DEBUG_PORT.println("SD card initialization failed.");
    return;
  }

  gpsPort.begin(9600);
  
}


void loop()
{
  while (gps.available( gpsPort )) {
    DEBUG_PORT.print( F("GPS tracking has been started\n") );
    
    float lat = 0.0;
    float lng = 0.0;
    String altt = "0";
    String speed = "0";

    fix = gps.read();

    DEBUG_PORT.print( F("Location: ") );
    DEBUG_PORT.print(gps.fix().dateTime);
    
    if (fix.valid.location) {
      lat = fix.latitude();
      lng = fix.longitude();
      DEBUG_PORT.print( lng, 6 );
      DEBUG_PORT.print( ',' );
      DEBUG_PORT.print( lat, 6 );
    }

    DEBUG_PORT.print( F(", Speed: ") );
    if (fix.valid.speed) {

      DEBUG_PORT.print(fix.speed_kph());
      speed = (String)fix.speed_kph();
    }

    DEBUG_PORT.print( F(", Altitude: ") );
    if (fix.valid.altitude) {
      DEBUG_PORT.print( fix.altitude() );
      altt = (String) fix.altitude();
    }

    DEBUG_PORT.println();

    // Try and append
    file = SD.open("gpsdata.csv", FILE_WRITE);

    if (file) {
      file.print(lng, 6);
      file.print(",");
      file.print(lat, 6);
      file.print(",");
      file.print(speed);
      file.println();
      file.close();
      Serial.println("File closed");
    }

    delay(60000);
  }

}