Esto esapp.module.ts He tratado de importar el mapa en un proyecto diferente y funcionó bien, pero en este proyecto no funciona.

    import { BrowserModule } from '@angular/platform-browser';
    import { NgModule } from '@angular/core';
    import {HttpModule} from '@angular/http';

    import { AppComponent } from './app.component';
    import { PagesComponent } from './pages/pages.component';

    @NgModule({
      declarations: [
        AppComponent,
        PagesComponent
      ],
      imports: [
        BrowserModule,
        HttpModule

      ],
      providers: [],
      bootstrap: [AppComponent]
    })
    export class AppModule { }

app.component.ts

import { Component } from '@angular/core';
import {PageService} from './page.service';

@Component({

  selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ["../assets/public/css/adminstyle.css",
            "../assets/public/css/demo.css",
          "../assets/public/css/style.css"
        ,"../assets/public/css/stylesheet.css"],
  providers:[PageService]
})
export class AppComponent {
  title = 'app';
}

page.service.ts

import {Injectable} from '@angular/core';
import {Http,Headers} from '@angular/http';

import 'rxjs/add/operator/map';

@Injectable({
  providedIn: 'root'
})
export class PageService {

  constructor(private http:Http) { 
  console.log('Task Service Initialized');

  }
}