Map Chart

Map charts can display data on a map using latitude/longitude, geohash, geocodes, and GeoJSON

This feature is currently in private preview. Please contact Codatum support to enable this feature for your workspace.

Data Formats

Map charts can display the following data formats on a map.

Latitude/Longitude

Draws objects at the specified latitude and longitude coordinates. Latitude and longitude should be specified as numeric columns. Available for the following render types:

• Pin

• Bubble

• Heatmap

• Flow

  • Requires two sets (source and target) of latitude/longitude information

Geohash

Draws objects at positions specified in Geohash format.

For the following render types, objects are drawn at the center of the specified geohash:

• Pin

• Bubble

• Heatmap

For the following render type, the area of the specified geohash is filled and drawn: (The size of the filled area varies depending on the precision of the specified geohash)

• Mesh

Geohash Examples

Below are examples of geohashes at different precision levels.

Geohash	Precision	Example Location	Area Size (approx.)
xn	2 characters	Tokyo area	630km × 500km
xn7	3 characters	Central Tokyo	78km × 78km
xn76	4 characters	Tokyo Station area	20km × 10km
xn76u	5 characters	Around Tokyo Station	2.4km × 2.4km
xn76ur	6 characters	Near Tokyo Station	610m × 300m
xn76urx	7 characters	Tokyo Station vicinity	76m × 76m
xn76urxk	8 characters	Around Tokyo Station	19m × 9m

BigQuery Usage Example

In BigQuery, you can use the ST_GEOHASH function to convert latitude and longitude data into geohashes. By converting to geohashes, you can efficiently aggregate and group data by area, rather than handling latitude and longitude individually.

Below is an example of using BigQuery's ST_GEOHASH function to convert latitude and longitude data into geohashes.

SELECT
  ST_GEOHASH(ST_GEOGPOINT(longitude, latitude), 6) AS geohash,
  COUNT(*) AS station_count
FROM
  `bigquery-public-data.new_york_citibike.citibike_stations`
GROUP BY
  geohash
ORDER BY
  station_count DESC

Geocode

Fills and draws the area associated with a geocode. Available for the following render type:

• Area

Geocodes should be specified as strings in the following format:

Granularity	Geocode Format	Geocode Example
Country	2-letter country code (ISO3166-1, uppercase)	US
Prefecture (Japan only)	"JP-"+2-digit prefecture code (JIS X 0402)	JP-13
Municipality (Japan only)	"JP-"+5-digit municipality code (JIS X 0402)	JP-13101
First 2 digits of postal code (Japan only)	"JP-POST-"+first 2 digits of postal code	JP-POST-10
First 3 digits of postal code (Japan only)	"JP-POST-"+first 3 digits of postal code	JP-POST-100

The geospatial data used for filling is a lightweight version processed from the following data:

• Global country border data: Natural Earth

• Japanese administrative boundary data: "National Land Numerical Information (Administrative Area Data)" (Ministry of Land, Infrastructure, Transport and Tourism)

• Postal code boundary data: Postal Code Boundary Data (Map Geography Sandbox)

Note that even if a geocode format is valid, geocodes not included in the above data cannot be drawn.

Geocode Samples

The following are sample geocodes. For a list of available geocodes, please refer to the Geocode List CSV file.

Geocode	Name
US	United States
JP	Japan
JP-01	Hokkaido
JP-02	Aomori Prefecture
JP-03	Iwate Prefecture
JP-01100	Sapporo City
JP-01101	Sapporo City, Chuo Ward
JP-01102	Sapporo City, Kita Ward
JP-01103	Sapporo City, Higashi Ward
JP-01202	Hakodate City
JP-01203	Otaru City
JP-01204	Asahikawa City
JP-POST-10	〒10X-XXXX
JP-POST-100	〒100-XXXX

GeoJSON

Draws GeoJSON-formatted geometry data on a map. Available for the following render types:

• Polygon

• Polyline

Specify JSON of the following geometry types as string type:

• Point

• LineString

• Polygon

• MultiPoint

• MultiLineString

• MultiPolygon

• GeometryCollection

GeoJSON Sample

{
  "type": "Polygon",
  "coordinates": [
    [
      [-73.9812, 40.7681],
      [-73.9581, 40.7681],
      [-73.9581, 40.8007],
      [-73.9812, 40.8007],
      [-73.9812, 40.7681]
    ]
  ]
}

BigQuery Usage Example

In BigQuery, you can use the ST_ASGEOJSON function to convert geometry data to GeoJSON format. The following example converts the county_geom column from the bigquery-public-data.geo_us_boundaries.counties table to GeoJSON format.

SELECT
  * EXCEPT (county_geom),
  ST_ASGEOJSON(county_geom) AS county_geom
FROM
  `bigquery-public-data.geo_us_boundaries.counties`
WHERE
  state_fips_code = '36'  -- New York

If the size of the geometry data to be drawn is large, it may exceed the query result size limit and cause an error. In such cases, you can use the ST_SIMPLIFY function to simplify the geometry data and reduce its size. (We recommend simplifying large geometry data to the minimum necessary size, as it can also affect rendering performance)

SELECT
  * EXCEPT (county_geom),
  ST_ASGEOJSON(ST_SIMPLIFY(county_geom, 1000)) AS county_geom
FROM
  `bigquery-public-data.geo_us_boundaries.counties`
WHERE
  state_fips_code = '36'  -- New York

Usage Limitations

Since map charts use WebGL to render maps, the following limitations apply:

• Cannot be rendered in browsers that do not support WebGL

• Due to WebGL context number limitations, when attempting to render many map charts simultaneously, previously rendered charts may be discarded

  • They can be re-displayed by re-rendering, but please be careful not to have too many map charts per page