MySQL query for WGS-84 longitude & latitude radius GPS distance calculation

WGS-84 Proximity Search with Longitude & Latitude decimal co-ordinates

Example: Hotel Burnham in Downtown Chicago is located at:
1 West Washington Street, Chicago, IL
Latitude: 41.883190
Longitude: -87.627940

I absolutely want to help some people out there with the same problem I
faced. I spent all night scanning lines of code trying SQL and C# code
that simply just DOES NOT work. There is TONS of crap code scattered
all over the internet, but very many great articles explaining how
everything works, so I piggybacked on the knowledge out there to get a
working solution. For those like me, you just want to use the code and
hit the ground running.

The basis of my calculation is derived from a Microsoft White Paper.

So here goes, d = distance, is the final output of this equation. R =
the earth's radius (and can be in m, km, mi or nm) The values 'a', 'b'
and 'c' are just steps to break the formula into digestable chunks:

a = sin(lat1)*sin(lat2)
b = cos(lat1)*cos(lat2)*cos(lon2-lon1)
c = acos(a+b)
d = R*c

The earth's radius is:
6378137 meters
6378.137 km
3963.191 miles
3441.596 nautical miles

Simply choose the value for R, for your desired distance results.
Example: R = 3963.191 (OR d = 3963.191*c) will return distance from
main point of interest in miles, use 6378.137 instead as the R
parameter and get a result in KM's

Other constants, MySQL actually has a function called "PI()" which I
will use in this example, but its precision is not quite as great as
the number below:
PI = 3.141592653589793

SELECT 3963.191 * ACOS( (SIN(PI()*41.883190/180)*SIN(PI()*MapLat/180))
+
(COS(PI()*41.883190/180)*cos(PI()*MapLat/180)*COS(PI()*MapLong/180-PI()*-87.
627940/180))
), Company, Address FROM boomtrek.poi WHERE City = 'Chicago'

The fields in my database are MapLat and MapLong for the decimal
degrees values that work with Google Maps WGS-84 standard. I found that
the majority of tutorials out there neglected to give much info on the
parameters being passed into the method, just simply the method.

NOTE: all latitude/longitude inputs must be converted into RADIANS!!

The calculate for decimal degrees like 'lat1' (41.883190) to radians
is:
PI() * lat1 / 180
OR
3.14159 * 41.883190 / 180

lon1 input is like this:
PI() * -87.627940 / 180
....to convert decimal degrees into radians.

lat1 & lon1 input parms - should be the fixed point where you want to
search proximity, this is the point of interest to find things nearby
it, in this case:
(1 West Washington Street, Chicago, IL)
Latitude: 41.883190
Longitude: -87.627940

MapLat = lat2 input parameter (MapLat = the MySQL field in the database
for the latitude geocoding)
MapLong = lon2 input parameter (MapLong is the MySQL longitude field in
the database)

For Mapping; tacking the same stuff as the SELECT clause on to the
WHERE clause one can find points within a 1.5 mile radius, and reduce
the resultset size, displaying all points on one map page, between
10-25 points should be a great number.

AND 3963.191 * ACOS( (SIN(PI()*41.883190/180)*SIN(PI()*MapLat/180)) +
(COS(PI()*41.883190/180)*cos(PI()*MapLat/180)*COS(PI()*MapLong/180-PI()*-87.
627940/180))
) <= 1.5 LIMIT 25

And finally; using an ORDER BY with the same stuff yet again you could
find the things closet to your proximity where you're standing or
driving:

ORDER BY 3963.191 * ACOS(
(SIN(PI()*41.883190/180)*SIN(PI()*MapLat/180)) +
(COS(PI()*41.883190/180)*cos(PI()*MapLat/180)*COS(PI()*MapLong/180-PI()*-87.
627940/180))
)

I really hope this was of use to some people, you can see the mapping
and proximity searching in action at Boomtrek Local Search:
http://www.boomtrek.com/search.aspx...ww.boomtrek.com
boomtrek@hotmail.com (MSN)