* example to process a CSV file containing data

 * about wind turbines in the USA

 * Source: https://eerscmap.usgs.gov/uswtdb/

 */

​

// An array of strings to hold the entire file

let strings = [];

​

// For scaling, we want to know the minimum and maximum latitude and longitude

let minLat;

let maxLat;

let minLong;

let maxLong;

​

function preload() {

  // The text from the file is loaded into an array.

  strings = loadStrings("uswtdb_v5_3_20230113.csv");

}

​

function setup() {

  createCanvas(500, 400);

  background(235);

​

  // Did we succeed to load anything?

  if (strings == null) {

    print("failed to load the file, stopping here");

​

    // this is an endless loop; it's a common way

    // to prevent a program from continuing when

    // something is so wrong that there is no sense

    // in continuing

    while (true) {}

  }

​

  print(

    "strings loaded from file successfully, read " + strings.length + " lines"

  );

​

  // Find the minimum and maximum latitude

  // and longitude

  findMinMaxLatLong();

}

​

function findMinMaxLatLong() {

  let singleRow = [];

​

  // loop over each row in the file

  for (let csvRowNumber = 1; csvRowNumber < strings.length; csvRowNumber++) {

    // get a single row and split that row

    // into individual words

    singleRow = split(strings[csvRowNumber], ",");

​

    // We know that the last two fields are the

    // latitude and longitude and so they are

    // numerical:

    let longitude = float(singleRow[25]);

    let latitude = float(singleRow[26]);

​

    // The file may be missing a field, in which case

    // the converstion to a float might have failed

    if (isNaN(longitude) || isNaN(latitude)) {

      print("conversion to float failed; skipping row " + csvRowNumber);

    } else {

      if (csvRowNumber == 1) {

        minLat = latitude - 10;

        maxLat = latitude + 10;

        minLong = longitude - 10;

        maxLong = longitude + 10;

      }

​

      if (latitude < minLat) minLat = latitude;

      if (latitude > maxLat) maxLat = latitude;

      if (longitude < minLong) minLong = longitude;

      if (longitude > maxLong) maxLong = longitude;

    }

  } // end of for() loop

​

  print("Latitude (min, max) = (" + minLat + "," + maxLat + ") ");

  print("Longitude (min, max) = (" + minLong + "," + maxLong + ")");

} // end of findMinMaxLatLong

​

let csvRowNumber = 1;

// Skip the first line, since we know it's a header

​

function draw() {

  let singleRow = [];

​

  // get a single row and split that row into

  // individual words

  singleRow = split(strings[csvRowNumber], ",");

​

  // This really slows things

  // down so use only when debugging

  //print("Row " +

  // csvRowNumber +

  //   " contains " +

  //   singleRow.length +

  //   " fields" );

​

  // We know that the last two fields are the

  // latitude and longitude and so they are

  // numerical:

  let longitude = float(singleRow[25]);

  let latitude = float(singleRow[26]);

​

  // use only when debugging

  // print("Latitude " +

  // latitude +

  //   " longitude " +

  //   longitude );

​

  // Check for non-numerical strings.

  if (isNaN(longitude) || isNaN(latitude)) {

    print("conversion to float failed; skipping row " + csvRowNumber);

  } else {

    // scale that to fit on our canvas

    //print(csvRowNumber);

    let ypos = map(latitude, minLat, maxLat, 0, height);

    let xpos = map(longitude, minLong, maxLong, 0, width);

​

    // Put a mark there

    point(xpos, ypos);

  } // end of valid data

​

  csvRowNumber++;

  if (csvRowNumber >= strings.length) {

    print("finished");

    noLoop();

  }

}