 
 A practical example would look like this:
 
-47.758949,-122.190746,map_47_758949_-122_190746.txt,
-47.6213,-122.3509,map_47_6213_-122_3509.txt
+47.758949,-122.190746,MAP001.txt,
+47.6213,-122.3509,MAP002.txt
 
 
 -----------------------

// SelectMap
// Determines which map to load.
// Takes in the current location as a waypoint and a string with the name of the file that
// contains the origins and file names of the maps. Determines which origin is closest to 
// the waypoint and returns it as a junction.
char* SelectMap(waypoint currentLocation, char* fileName)
{

  Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin 
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
  // or the SD library functions will not work. 
   pinMode(SS, OUTPUT);
   
  if (!SD.begin(chipSelect)) {
    Serial.println("initialization failed!");
    return NULL;
  }
  Serial.println("initialization done.");
  
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  myFile = SD.open("test.txt", FILE_WRITE);
  
  // if the file opened okay, write to it:
  if (myFile) {
    Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
	// close the file:
    myFile.close();
    Serial.println("done.");
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }
  
  // re-open the file for reading:
  myFile = SD.open("test.txt");
  if (myFile) {
    Serial.println("test.txt:");
    
    // read from the file until there's nothing else in it:
    while (myFile.available()) {
      Serial.write(myFile.read());
    }
    // close the file:
    myFile.close();
  } else {
  	// if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }

  // Define serial connection to SD card
  // Attempt to load file

documentation to implement it, we decided to focus on implementing a file system with
comma delimited values for the data we need to build junction objects.

-----------------------
|     MAP_DEFS.txt    |
-----------------------

This file provides the latitude and longitude coordinates for each of the maps, followed
