How to return value of longtide and latitude from json using angular 7?

my url as following :

http://192.168.7.xxx:9200/location/_doc/27737

json returned from url above is :

{"_index":"location","_type":"_doc","_id":"27737","_version":1,"_seq_no":5577,"_primary_term":1,"found":true,"_source":{"Locid":27737,"GPS1":"25.0173, 121.462","GPS2":"25°01'02.2\"N 121°27'44.8\"E","CompanyID":1005070,"ads":"142 Sec. 1, HsIn Nan Rd cung Ko Dšst, New Taipei City, Taiwan","Crid":75,"con":"Taiwan","Ctid":5894,"Cn":"Zhonghe District","pushdate":"2019-12-26T03:38:20.883"}}

I need to return two values from GPS1 :

longtiude : 25.0173

latitude : 121.462

Based on LocationId parameter :27737

So that I need to create service

take location id parameters

and return two values of GPS1
Longtude
And
latitude

then set values returned of longtude and latitude

on ngOinInit Event

How to create service then call it on ngOnInit

ngOnInit  
{  
call service here  
}