Georeference by Longitude and Latitude

Analysis Guides

Georeference by Longitude and Latitude

Georeferencing is a CARTO service that gathers location data, from many different sources, to get the geographical coordinates associated with latitude/longitude columns, city names, postal codes, administrative boundaries, IP addresses, or street addresses. Since CARTO uses coordinates to plot data, the more finite your data (such as an address), the better your results (versus a city name).

The Georeference analysis in CARTO Builder enables you to generate location coordinates directly from a map layer. For this guide, let's convert the location of Paris addresses by latitude and longitude.

Geocode Data into Point Geometries

We will use the location of Paris addresses, provided by openaddresses.io. This example displays the intense flooding that occurred in Paris; similar to the flood that occurred in 1910. The data is derived from Open Data of Paris, and the results are applied as point coordinates.

  1. Import the template .carto file, packaged from "Download resources" of this guide and create the map. Builder opens with Paris data as the first map layer, Natural_water as the second map layer, and Flood_zone as the third map layer.

    Click on "Download resources" from this guide to download the zip file to your local machine. Extract the zip file to view the .carto file(s) used for this guide.

    Notice that the Paris map layer does not identify what type of geometry the data contains.

    Paris layer with no geometries

  2. Switch to the Data View of the Paris map layer and you will notice that there are various columns with address information.

    The Data View and Map View appear as icons on your map visualization when a map layer is selected. Click to switch between viewing your connected dataset as a table, or show the map view of your data.

    Since the original data is in French, the translation of languages may complicate the geocoding of data. We will use the lon and lat columns from our dataset to georeference all of the geometry coordinates.

  3. Click the ANALYSIS tab to add an analysis to the Paris map layer.

  4. Select Georeference from the Add a new analysis options.

    • Keep Longitude and Latitude selected as the Georeference TYPE.

    • You must enter the LATITUDE and LONGITUDE parameters before applying the analysis. For this example, select the lat and lon columns from the Paris dataset.

    • Click APPLY. The analysis confirmation dialog appears, which you can use to apply styling.

      Georeference result

  5. Click STYLE THIS ANALYSIS to visually enhance the buildings within the flood-zone.

    • Click on the SIZE value and change it to 1.5. (Be sure to click on the size, not the color, from the SIZE/COLOR options).
    • Click on the COLOR. The SOLID tab opens by default. Use the color modifier to change the solid fill color to black.
    • Click on the STROKE size and change the value to 0.

    Style the analysis

    Optionally, download the final .carto file from the "Download resources" of this guide to see the styling options that were applied.

The analysis geocoded the Paris data into point geometries, and the Georeference analysis is linked to the map layer. You can continue to explore the point geometry data for Paris.

Georeference analysis applied to Paris layer

Geocode with the API

If you are a developer and have access to the CARTO Engine's to manage your data, view the Geocoding Functions that can be applied with the Data Services API.