Adafruit GPS to OLED

/*
 *  Adafruit GPS deg-Min with OLED and Ultimate GPS Wing (ESP32)
 *  @author [Zachary Hunter]
*/
#include <Adafruit_GPS.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <math.h>;
#define GPSSerial Serial2

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 32, &Wire);

Adafruit_GPS GPS(&GPSSerial);
#define GPSECHO false

double convertCoords(double in_coords) {
  double f = in_coords;
  int firstDigits = ((int)f) / 100;
  double nextDigits = f - (double)(firstDigits * 100);
  double finalDigits = (double)(firstDigits + nextDigits / 60.0);
  return finalDigits;
}

uint32_t timer = millis();

void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.display();

  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);

  delay(1000);

  // Ask for firmware version
  GPSSerial.println(PMTK_Q_RELEASE);

  display.setTextSize(1);
  display.setTextColor(WHITE);
}

void loop() {

  char c = GPS.read();

  if (GPSECHO)
    if (c) Serial.print(c);
  if (GPS.newNMEAreceived()) {
    Serial.println(GPS.lastNMEA());
    if (!GPS.parse(GPS.lastNMEA()))
      return;
  }
  if (timer > millis()) timer = millis();
  if (millis() - timer > 2000) {
    timer = millis(); // reset the timer
    display.clearDisplay();
    display.setCursor(0, 0);
    Serial.print("\nTime: ");
    Serial.print((GPS.hour, DEC) + 2);
    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);

    display.print("Fix: ");
    display.print((int)GPS.fix);
    display.print(" / Quality: ");
    display.println((int)GPS.fixquality);

    display.print((GPS.hour, DEC) + 2);
    display.print(':');
    display.print(GPS.minute, DEC);
    display.print(':');
    display.print(GPS.seconds, DEC);
    display.print('.');
    display.println(GPS.milliseconds);
    if (GPS.fix) {
      Serial.print("Location: ");
      Serial.print(convertCoords(GPS.latitude));
      Serial.print(GPS.lat);
      Serial.print(", ");
      Serial.print(convertCoords(GPS.longitude));
      Serial.println(GPS.lon);

      display.print(convertCoords(GPS.latitude));
      display.print(GPS.lat);
      display.print(", -");
      display.print(convertCoords(GPS.longitude));
      display.print(GPS.lon);

      Serial.print("Speed (knots): ");
      Serial.println(GPS.speed);
      Serial.print("Angle: ");
      Serial.println(GPS.angle);
      Serial.print("Altitude: "); Serial.println(GPS.altitude);
      Serial.print("Satellites: "); Serial.println((int)GPS.satellites);
      display.print("\nSatellites: "); display.println((int)GPS.satellites);
    }
    display.display();
  }
}