Sistem Informasi Geografis

http://www.apapengertianahli.com/2015/06/10-pengertian-sistem-menurut-para-ahli.html

http://www.definisi-pengertian.com/2015/03/definisi-dan-pengertian-informasi.html

http://brainly.co.id/tugas/283905

https://inwebsite.wordpress.com/tag/pengertian-latitude-longitude/

http://www.pengertianahli.com/2013/10/pengertian-sig-sistem-informasi.html

http://inigis.com/mengenal-mapserver/