make a big query adapted macro

Author: bastienboutonnet

macros/geo/haversine_distance.sql

@@ -6,6 +6,10 @@ http://daynebatten.com/2015/09/latitude-longitude-distance-sql/
 The arguments should be float type.
 #}
 
+{% macro degrees_to_radians(degrees) -%}
+    acos(-1) * {{degrees}} / 180
+{%- endmacro %}
+
 {% macro haversine_distance(lat1,lon1,lat2,lon2,unit='mi') -%}
     {{ return(adapter.dispatch('haversine_distance', packages = dbt_utils._get_utils_namespaces())(lat1,lon1,lat2,lon2,unit)) }}
 {% endmacro %}
@@ -23,3 +27,24 @@ The arguments should be float type.
     pow((sin(radians(({{lon2}} - {{lon1}}) / 2))), 2))) {{conversion_rate}}
 
 {%- endmacro %}
+
+
+
+{% macro bigquery__haversine_distance(lat1,lon1,lat2,lon2,unit) -%}
+{% set r_lat1 = dbt_utils.degrees_to_radians(lat1) %}
+{% set r_lat2 = dbt_utils.degrees_to_radians(lat2) %}
+{% set r_lon1 = dbt_utils.degrees_to_radians(lon1) %}
+{% set r_lon2 = dbt_utils.degrees_to_radians(lon2) %}
+{# vanilla macro is in miles #}
+    {% set conversion_rate = '' %}
+{% if unit == 'km' %}
+{# we multiply miles result to get it in kms #}
+    {% set conversion_rate = '* 1.60934' %}
+{% endif %}
+
+    2 * 3961 * asin(sqrt(pow(sin(({{r_lat2}} - {{r_lat1}}) / 2), 2) +
+    cos({{r_lat1}}) * cos({{r_lat2}}) *
+    pow(sin(({{r_lon2}} - {{r_lon1}}) / 2), 2))) {{conversion_rate}}
+
+{%- endmacro %}
+