[maps] Extra decimals added in fractional part of labels in maps when using vector tiles

[nreese]

Problem

Vector tiles read the value from the fields option that uses _source but it then cast the value to the fields type. Fields mapped as float are displayed as the float representation. For example, 2.3 is displayed as 2.299999952316284.

It can be easily reproduced by doing:

PUT /test_float
{
  "mappings": {
    "properties": {
      "field":    { "type": "float" },
      "location" : {"type": "geo_point" }
    }
  }
}

POST test_float/_doc
{
  "field" : 2.3, "location" : "POINT(0 0)"
}

GET test_float/_mvt/location/0/0/0
{
  "fields": ["field"],
  "grid_precision" : 0
}

Potential solutions

There is no way to format that value in the vector tiles API.

One possible solution is to allow users to specify a maplibre expression to format the label, for example, users could configure number-format

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[ThomThomson]

Closing this as we have added it to our icebox for the time being.