CSV files can be used to display location-based information as point data layers. This is useful when working with datasets containing individual locations, such as buildings, monitoring stations, planning applications or other geographically referenced information. Once uploaded, the points can be viewed as a data layer alongside the other content in your project.

Preparing the CSV

A CSV file uses a simple tabular structure, with each row representing an individual point and each column containing information about that point - two columns define the point’s position (X and Y), while any additional columns are imported as attributes. These attributes can contain descriptive information such as a name, category, status or reference number. For the Hub to interpret the data correctly, the file needs to follow a few formatting and naming conventions.

• File format: The file must be comma-separated, not semicolon- or tab-separated. In Excel, select Save As › CSV UTF-8 (Comma delimited).
• Header row: The first row must contain column headings identifying each field.
• Coordinate columns: The file must contain exactly one X column and one Y column, using one of the recognised column names listed below.
• Coordinate values: Both coordinate columns must contain numeric values for every data row. Blank lines are ignored.
• Data rows: At least one row of coordinates must be present beneath the header.
• Numeric value: Include a numeric value in both coordinate columns for every data row. Blank lines are ignored.

The coordinate columns can appear anywhere in the file, and their names are not case-sensitive.

Recognised coordinate column names

The CSV must contain one column identifying the X coordinate and one identifying the Y coordinate. Column names are not case-sensitive.

X coordinate (longitude or easting)

The following column names are supported:

• x
• lon
• long
• longitude
• easting
• bng_e

Y coordinate (latitude or northing)

The following column names are supported:

• y
• lat
• latitude
• northing
• bng_n

Only one column from each group can be used. For example, a file containing both x and longitude columns will be rejected because both are recognised as X coordinates.

Supported geometry

CSV uploads currently support point data only. Lines and polygons are not supported.

Coordinates are two-dimensional. If the file includes a height or Z column, it will be imported as an attribute but will not affect the position of the points.

Choose the right coordinate system

When uploading CSV, the coordinate system used by the coordinates in the file must be selected. This is important because the coordinate system determines how the numerical values are interpreted and where the points appear geographically. For example, longitude and latitude values use a different coordinate system from British National Grid eastings and northings.

The following coordinate systems are supported:

WGS 84 / EPSG 4326

Used for longitude and latitude coordinates, commonly found in GPS data and geographic datasets.

Example: -0.1281, 51.5080

In this example:

• Longitude is X (-0.1281).
• Latitude is Y (51.5080).

Select WGS 84 / EPSG 4326 when uploading a file containing these coordinates.

British National Grid / EPSG 27700

Used for easting and northing coordinates, commonly found in UK mapping and surveying datasets.

Example: 530010, 180440

In this example:

• Easting is X (530010).
• Northing is Y (180440).

Select British National Grid / EPSG 27700 when uploading a file containing these coordinates.

Upload your file

CSV files can be uploaded through the data layer upload option in the Hub.

1. In the Hub, go to Upload › Data layers.
2. Select the .csv file.
3. Choose the coordinate system that matches the coordinates in your file.
4. Complete the upload.

If the file doesn’t meet the required format, the validation screen will display an error explaining what needs to be corrected.

A coordinate system must be selected for every CSV upload. Automatic detection is not available because CSV files do not contain information identifying their coordinate system.

CSV templates and examples

When preparing a CSV for the first time, one of the templates below can be used as a starting point. Each template contains example data for three London landmarks. The sample rows can be replaced with your own coordinates and attributes.

• WGS 84 template:data-layer-points-wgs84.csv download link
• British National Grid template:data-layer-points-bng.csv download link

Both templates include name and category columns as examples of additional attributes. These columns can be renamed or removed, and additional fields can be added to suit your dataset.

The coordinate system selected during upload must match the coordinate values in the original file.

Common upload errors

For the CSV fails validation, the upload screen will display an error message. The following examples explain some common messages and how to resolve them. The messages shown here are shortened for readability.

The CSV file is empty.

Check that you’ve selected the correct file and that it contains data.

The CSV uses semicolons or tabs to separate columns.

Save the file using commas as separators. In Excel, select CSV UTF-8 (Comma delimited).

The first row must be a header naming the coordinate columns.

Add a header row containing column names, such as longitude,latitude or easting,northing.

The CSV needs an X or Y column. Columns found: …

Rename the coordinate columns using one of the recognised names listed in the CSV file requirements section.

The CSV has more than one X or Y column.

Rename or remove duplicate coordinate columns so that exactly one X column and one Y column remain.

The CSV has a header but no rows of coordinates.

Add at least one row containing coordinate values beneath the header.

Row(s) N have a missing or non-numeric value.

Every data row must contain a numeric value in both coordinate columns. If any row fails validation, the upload will be rejected. Correct the affected values or remove the invalid rows before uploading again.

A coordinate system is required for CSV files.

Select the coordinate system that matches the coordinates in your file.

If your points upload successfully but appear in the wrong location, check that you’ve selected the correct coordinate system and that the X and Y values haven’t been swapped.