Oak | Convert latitude-longitude format

Convert latitude-longitude format

haversine gps decimal DMS latitude longitude easy

Convert latitude-longitude coordinates from decimal degrees to DMS (degrees-minutes-seconds).

Details

Lat-Long formats

Degrees-Minutes-Seconds (DMS): 1°24'58.6"N 103°54'54.6"E
Decimal-Minutes: 124.97666667, 10354.91
Decimal Degrees: 1.41627010, 103.91517884

Steps

Plug in the Oak PCB to the computer
(Option A) Ensure the PCB can be detected with ls -al /dev/cu.usbmodem and arduino-cli board list. Run make to compile and upload the code to the board.
(Option B) Ensure the board can be detected with Arduino IDE. Compile and upload the code to the board.

Serial console

Serial output from the firmware.

Code

Download code

#define EARTH_RADIUS 6371.0  // km

float lat1 = 1.42163183;
float long1 = 103.91052423;
float lat2 = 1.4172271;
float long2 = 103.91538793;
float latDM = 124.97666667;
float longDM = 10354.91;

void setup() {
  SerialUSB.begin(9600);
  while (!SerialUSB) { }
  SerialUSB.println("Latitude, Longitude conversions...");

  SerialUSB.println("\nPunggol point lat-long:");
  convertDecToDMS(lat1, long1);

  SerialUSB.println("\nConey Island West point lat-long:");
  convertDecToDMS(lat2, long2);

  SerialUSB.println("\nHaversine Distance:");
  getHaversineDistance(lat1, long1, lat2, long2);

  SerialUSB.println("\nConey Island West Entrance:");
  convertDMtoDMStoDec(latDM, longDM);
}

void loop() { }

// Convert a latitude and longitude
// from decimal degrees to DMS (degrees-minutes-seconds)
void convertDecToDMS(float lat, float lon) {
  SerialUSB.println("in Decimals: " + String(lat, 6) + ", " + String(lon, 6));

  SerialUSB.print("in DMS: ");
  // Convert latitude to DMS
  int latDegrees = (int)lat;
  float latMinutes = (lat - latDegrees) * 60.0;
  float latSeconds = (latMinutes - (int)latMinutes) * 60.0;
  SerialUSB.print(latDegrees);
  SerialUSB.print(" ");
  SerialUSB.print(latMinutes);
  SerialUSB.print("' ");
  SerialUSB.print(latSeconds);
  SerialUSB.print("\"");

  // Convert longitude to DMS
  int lonDegrees = (int)lon;
  float lonMinutes = (lon - lonDegrees) * 60.0;
  float lonSeconds = (lonMinutes - (int)lonMinutes) * 60.0;
  SerialUSB.print(",  ");
  SerialUSB.print(lonDegrees);
  SerialUSB.print(" ");
  SerialUSB.print(lonMinutes);
  SerialUSB.print("' ");
  SerialUSB.print(lonSeconds);
  SerialUSB.println("\"");
}

void getHaversineDistance(float lat1, float lon1, float lat2, float lon2) {
  float dLat = (lat2 - lat1) * DEG_TO_RAD;
  float dLon = (lon2 - lon1) * DEG_TO_RAD;
  float lat1Rad = lat1 * DEG_TO_RAD;
  float lat2Rad = lat2 * DEG_TO_RAD;

  float a = sin(dLat / 2) * sin(dLat / 2) +
    sin(dLon / 2) * sin(dLon / 2) * cos(lat1Rad) * cos(lat2Rad);
  float c = 2 * atan2(sqrt(a), sqrt(1 - a));
  float d = EARTH_RADIUS * c;

  SerialUSB.print(d);
  SerialUSB.println(" km");
}

void convertDMtoDMStoDec(float lat, float lon) {
  SerialUSB.println(
    "in DM: "
    + String(lat, 6)
    + ", "
    + String(lon, 6));

  // Convert DM to DMS
  int latDM = (int)lat;
  String latDMString = String(latDM);
  String latD = latDMString.substring(0, latDMString.length() - 2);
  String latM = latDMString.substring(latDMString.length() - 2, latDMString.length());
  float latS = (lat - (int)lat) * 60.0;
  SerialUSB.print("in DMS: ");
  SerialUSB.print(latD + " ");
  SerialUSB.print(latM + "' ");
  SerialUSB.print(String(latS) + "\",  ");

  int lonDM = (int)lon;
  String lonDMString = String(lonDM);
  String lonD = lonDMString.substring(0, lonDMString.length() - 2);
  String lonM = lonDMString.substring(
    lonDMString.length() - 2, lonDMString.length());
  float lonS = (lon - (int)lon) * 60.0;
  SerialUSB.print(lonD + " ");
  SerialUSB.print(lonM + "' ");
  SerialUSB.println(String(lonS) + "\"");

  // Convert DMS to Dec
  float latDec = (latD.toFloat()
    + (latM.toFloat() / 60.0)
    + (latS / 3600.0));
  float lonDec = (lonD.toFloat()
    + (lonM.toFloat() / 60.0)
    + (lonS / 3600.0));
  SerialUSB.println("in Decimals: "
    + String(latDec, 6)
    + ", "
    + String(lonDec, 6));
}

Makefile

BOARD?=hutscape:samd:oak
PORT := $(shell ls /dev/cu.usbmodem*)
BUILD=build

.PHONY: default lint all flash clean

default: lint all flash clean

lint:
	cpplint --extensions=ino --filter=-legal/copyright,-whitespace/line_length,-readability/casting,-readability/todo *.ino

all:
	arduino-cli compile --fqbn $(BOARD) --output-dir $(BUILD) ./

flash:
	arduino-cli upload -p $(PORT) --fqbn $(BOARD) --input-dir $(BUILD) --verbose

clean:
	rm -r build

References

https://www.latlong.net/lat-long-dms.html