csv2geojson

You can include csv2geojson directly in a browser environment by referencing the latest build via npmcdn:

https://npmcdn.com/csv2geojson@latest/csv2geojson.js

<script src="https://npmcdn.com/csv2geojson@latest/csv2geojson.js"></script>

You can install csv2geojson globally and use it to convert CSV or TSV files to GeoJSON via the command line. By default, it looks for latitude and longitude columns using case-insensitive patterns like /^Lat/i.

npm install -g csv2geojson
csv2geojson geodata.csv > geodata.geojson

To use the library in a Node.js project, install it as a dependency and use the csv2geojson.csv2geojson method. This method accepts a CSV string and an optional configuration object, and returns the data via a callback.

var csv2geojson = require('csv2geojson');

// Basic usage with default settings
csv2geojson.csv2geojson(csvString, function(err, data) {
    // err has any parsing errors
    // data is the GeoJSON FeatureCollection
});

// Usage with explicit configuration
csv2geojson.csv2geojson(csvString, {
    latfield: 'LATFIELDNAME',
    lonfield: 'LONFIELDNAME',
    delimiter: ','
}, function(err, data) {
    // err has any parsing errors
    // data is the GeoJSON FeatureCollection
});

The following methods are available in the Node.js API:

• csv2geojson.csv2geojson(csvString, [options], callback): Parses a CSV/TSV string into a GeoJSON FeatureCollection. options can include latfield, lonfield, and delimiter. delimiter can be a specific character (e.g., ',', ' ', '|') or 'auto' to attempt to detect the best delimiter from ,, , |, or ;.
• csv2geojson.dsv(delimiter).parse(dsvString): Uses the dsv library for barebones DSV parsing.
• csv2geojson.auto(dsvString): Automatically chooses a delimiter and parses the string.
• csv2geojson.toPolygon(gj): Converts a GeoJSON object of points into a Polygon based on the coordinate order.
• csv2geojson.toLine(gj): Converts a GeoJSON object of points into a LineString based on the coordinate order.

When using the CLI, you can specify the following options to control the conversion process:

Usage: csv2geojson --lat [string] --lon [string] --line [boolean] --delimiter [string] FILE

Options:
  --lat        the name of the latitude column
  --lon        the name of the longitude column
  --line       whether or not to output points as a LineString  [default: false]
  --delimiter  the type of delimiter                            [default: ","]
  --numeric-fields comma separated list of fields to convert to numbers

You can use the auto function to parse a CSV string by automatically detecting the delimiter (supporting ,, ;, \t, and |). It selects the delimiter that results in the highest number of columns (arity) consistently across all rows.

Alternatively, when calling csv2geojson, you can set the delimiter option to 'auto'.

const { auto } = require('csv2geojson');

const data = 'name;lat;lon\nTest;45;-122';
const parsed = auto(data);

// Or in csv2geojson
csv2geojson(data, { delimiter: 'auto' }, (err, geojson) => {
    // ...
});

The library provides utility functions to check if a string matches common latitude or longitude header patterns using regular expressions.

• isLat(f): Returns true if the string f matches latitude patterns (e.g., 'Lat', 'Latitude').
• isLon(f): Returns true if the string f matches longitude patterns (e.g., 'Lon', 'Long', 'Longitude').
• guessLatHeader(row): Given a parsed row object, returns the key name that most likely represents latitude.
• guessLonHeader(row): Given a parsed row object, returns the key name that most likely represents longitude.

If you have a GeoJSON FeatureCollection consisting of Point features, you can aggregate them into a single geometry using toLine or toPolygon.

• toLine(gj): Creates a FeatureCollection containing a single LineString feature. The coordinates are taken from the points in the input, and properties are aggregated into arrays (one entry per original feature) within the new feature's properties.
• toPolygon(gj): Creates a FeatureCollection containing a single Polygon feature. The coordinates are taken from the points in the input (as the exterior ring), and properties are aggregated into arrays.

const { toLine, toPolygon } = require('csv2geojson');

// Assuming 'geojson' is a FeatureCollection of Points
const line = toLine(geojson);
const polygon = toPolygon(geojson);

You can use csv2geojson as a command-line utility to convert CSV or TSV files into GeoJSON. The tool accepts a file path as a positional argument or reads from stdin. If no file is provided, it defaults to reading from standard input.

./csv2geojson --lat [latitude_column_name] --lon [longitude_column_name] [FILE]