[Maps] adding layers with geo_shape linestring bug

[babadofar]

Kibana version: Kibana 7.0.0.beta1

**Elasticsearch version:**7.0.0.beta1

Describe the bug:
Adding documents containing geo_shape Linestring to an elasticsearch index. Using the "add layers from an elasticsearch index feature". It fails. On further inspection it appears the error is that the geo_bounds aggregation does not work with geo_shape.

Steps to reproduce:

1. Create this document
   POST gps_test/_doc/1
   {
   "poslist":
   { "type": "LINESTRING",
   "coordinates": [[10.491832, 59.941252],[10.491833, 59.941252],[10.491898, 59.941263]]
   }
   }
   2
   ADD GPS_TEST as an index pattern
   Go to the Kibana maps app. Select option to add layer from an Elasticsearch index. Seect the Gps_test index, it correctly suggest to use the field poslist.
2. It does not work

Expected behavior:

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):
Inspecting the request reveals this query:
GET gps_test/_search
{
"size": 0,
"aggs": {
"1": {
"geo_bounds": {
"field": "poslist"
}
}
},
"_source": {
"excludes": []
},
"stored_fields": [
"*"
],
"script_fields": {},
"docvalue_fields": [],
"query": {
"bool": {
"must": [],
"filter": [
{
"match_all": {}
}
],
"should": [],
"must_not": []
}
}
}
Error returned:
Running the query in Kibana console returns this error:

"type": "illegal_argument_exception",
"reason": "Fielddata is not supported on field [poslist] of type [geo_shape]"

Any additional context:

[thomasneirynck]

more discussion here https://discuss.elastic.co/t/linestring-does-not-display-on-maps-app/168737/5

[elasticmachine]

Pinging @elastic/kibana-gis

[nreese]

@babadofar Did you click "fit to data" to trigger the error? Did you line strings get rendered?

[nreese]

https://github.com/elastic/kibana/blob/master/x-pack/plugins/maps/public/shared/layers/sources/es_source.js#L78

[thomasneirynck]

see corresponding feature request in ES elastic/elasticsearch#7574