How to include external page to wordpress page?

I have one external page (google_map.php) which contain code to display google map information based on the selection criteria.

And in the wordpress page I want to display the google map which is coded in google_map.php.

I want to ask that how can I add google_map.php page in my wordpress page?

Or other option,

Can i directly add my google_map.php page code to the wordpress page?
I don’t want to use any plugin to support php code in the wordpress page like Exec-PHP plugin.

Which is the better way?

It is actually very simple. just

• add the following text in at begining of google_map.php page
• upload this page to your theme folder.
• go to dashboard to create a page, when create a page chose page telmplate: google map.

that is it, you can read more here

<?php
/*
 Template Name: google map
*/
?>