If the top-level type is just a type name, you can omit it from the elements of the literal.
package main
import "fmt"
type Vertex struct {
Lat, Long float64
}
var m = map[string]Vertex{
"Bell Labs": {40.68433, -74.39967},
"Google": {37.42202, -122.08408},
func main() {
fmt.Println(m)