Gps bike computer

/*

-----------Bike comuter-----------
----by Trybulski Mikolaj----------
*/

//gps libaries
#include <TinyGPS++.h>
#include <SoftwareSerial.h>

//lcd libaries
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>

//variables used for distance calculations
float latold;
float longold;
float wholedistance;

// The TinyGPS++ object
TinyGPSPlus gps;

// The serial connection to the GPS device
SoftwareSerial ss(7, 6); //tx (on gps) - 7, rx (on gps) - 6

//lcd settin

//pinout 9 CLK , 10 DIN , 11 DC , 12 CE , 2 RST , 8  BL 
const int clk = 9;
const int din = 10;
const int dc = 11;
const int ce = 12;
const int rst = 2;
const int bl = 8; //low - on, high - off

Adafruit_PCD8544 display = Adafruit_PCD8544(clk, din, dc, ce, rst);



void setup(){
  wholedistance = 0;
  latold = 0;
  longold = 0;
  
  ss.begin(9600);
  delay(300);
  pinMode(bl, OUTPUT);
 digitalWrite(bl, LOW);
  display.begin();
  display.setContrast(60);
 display.clearDisplay();
 
 display.setTextColor(BLACK);
 display.setCursor(0,0);
  display.setTextSize(1);
  display.print("Bike computer v1.0, made by Trybulski Mikolaj  ");
    display.display();
    delay(2000);
 display.clearDisplay();
 display.setCursor(0,0);
  display.setTextSize(2);
  display.print("waitingfor gps... ");
    display.display();
}

void loop(){
  display.clearDisplay();
   display.setTextColor(BLACK);
  // This sketch displays information every time a new sentence is correctly encoded.
  while (ss.available() > 0){
    gps.encode(ss.read());

    
    if (gps.location.isUpdated()){

    //dist calculations
  if(latold == 0 || longold == 0){//dont calculate using 0 coordinates (which are set for stary value)
  latold = gps.location.lat();//update ealier position
  longold = gps.location.lng();
  delay(300);
    }
    else{
  if(gps.location.lat() == latold || gps.location.lng() == longold){
    delay(1000);
    } 
  else{
  float distLat = abs(gps.location.lat() - latold) * 111194.9;
  float distLong = 111194.9 * abs(gps.location.lng() - longold) * cos(radians((gps.location.lat() + latold) / 2));
  float distance = sqrt(pow(distLat, 2) + pow(distLong, 2));        // equation form https://www.instructables.com/Distance-measuring-and-more-device-using-Arduino-a/
  latold = gps.location.lat();//update ealier position
  longold = gps.location.lng();
  wholedistance = distance + wholedistance; // add newly calculated distance to ealier one for trip distance
    }
    }
    //dist display
  display.setTextSize(1.5);
  display.setCursor(0,25);
  display.print(wholedistance / 1000);
  display.println("km");
  
  int readvalue = gps.course.deg(); //define and round heading
  int speedo = gps.speed.kmph(); // define and round speed
 
  display.setCursor(0,0);
  display.setTextSize(3);
  display.print(speedo);
  display.setTextSize(1);
  display.print("kph ");
  display.setTextSize(2);
  
  if (readvalue >=338 || readvalue < 22){
    display.println("N");
    } 
  else if (readvalue >= 22 && readvalue < 68)
  {
    display.println("NE");
    }
    else if (readvalue >= 68 && readvalue < 113)
  {
    display.println("E");
    }
      else if (readvalue >= 113 && readvalue < 158)
  {
    display.println("SE");
    }
     else if (readvalue >= 158 && readvalue < 203)
  {
    display.println("S");
    }
    else if (readvalue >= 203 && readvalue < 248)
  {
    display.println("SW");
    }
   else if (readvalue >= 248 && readvalue < 293)
  {
   display.println("W");
    }
   else if (readvalue >= 293 && readvalue < 338)
  {
  display.println("NW");
    }

 display.display();
  delay(1000);  //wait. we dont need to update so many times
  
    }
  }
}