let backTabledata = [
  {
    id:'126652',
    no: '1',
    longitude: '103.94292',
    latitude: '30.620123',
    altitude: 501.00143,
    distance:'--'
  }, {
    id:'122855',
    no: '2',
    longitude: '103.94292',
    latitude: '30.620123',
    altitude: 501.00143,
    distance:'258.25'
  }, {
    id:'1285569',
    no: '3',
    longitude: '103.94292',
    latitude: '30.620123',
    altitude: 501.00143,
    distance:'253'
  }, {
    id:'1222555',
    no: '4',
    longitude: '103.94292',
    latitude: '30.620123',
    altitude: 501.00143,
    distance:'253'
  }];
for(let i in backTabledata){
  //console.log(data[i]);
  backTabledata[i].longitudeflag = false;
  backTabledata[i].latitudeflag = false;
  backTabledata[i].altitudeflag = false;
}
this.tableData = backTabledata;