I want to delimit a radius from a central coordinate (the red marker in the figure) and, from a set of coordinates (the green markers), check if they are within the area delimited by this radius. >
I need a real example, a sample project on Android.
As you said, if storage is being done in a MySQL database on the server, I imagine you have a call via webservice to fetch this data. Therefore, you can determine your question in query .
Assuming you have a table with the columns lat and lng for the coordinates and passing its reference point (here I will use as an example the values -19.83996 and -43.94910 ), just do something like this:
SELECT *, (6371 *
acos(
cos(radians(-19.83996)) *
cos(radians(lat)) *
cos(radians(-43.94910) - radians(lng)) +
sin(radians(-19.83996)) *
sin(radians(lat))
)) AS distance
FROM tabela HAVING distance <= 5
This will get you all locations that are within
More gold !!!
SELECT *,(RAIO_TERRESTRE *
acos(
cos(radians(PARAMETRO_LATITUDE)) *
cos(radians(COLUNA_LATITUDE)) *
cos(radians(PARAMETRO_LONGITUDE) - radians(COLUNA_LONGITUDE)) +
sin(radians(PARAMETRO_LATITUDE)) *
sin(radians(COLUNA_LATITUDE))
)) AS CAMPOLATITUDE
FROM TABELA HAVING CAMPOLATITUDE <= KM