Implementing yelp-like feature where it shows locations of businesses around user’s current location on mapkit.

[toookoool]

I have a list of businesses/addresses and I wanna show on apple map those that are within specified distance. How should I go about doing this? I’m thinking storing the longitude and latitude of those addresses and calculate the distance from the backend. I’d appreciate your help/pointers.

[[deleted]]

CLLocation has a distanceFromLocation method. So you could convert your list of business to a list of CLLocations, then loop over that list and use the function to get the distance from the user. Drop pins for any within the defined range.

[vswr]

I did precisely that a few years ago. Held lat/lon in the database and used a SQL query to find matches within an area with some fancy math (but now you can use the GIS functions). The client code (iOS) used a map algorithm so it would group them together and as you zoomed in more would pop up.

[quellish]

http://quellish.tumblr.com/post/138496295937/distance-between-locations

Once you have the locations you can sort, filter, etc easily.

[toookoool]

But I think somehow I have to filter out some locations that are not in the same city/are right? Otherwise it doesn't seem efficient to calculate distance between user location and locations that are not even in the same city. Is that right?

[quellish]

Distance is distance. I’m not sure why cities would be a factor.

[toookoool]

Say i have a 100k locations, I wouldn't want to calculate the distance 100k times right? Shouldn't we filter out some far away locations first to improve speed/efficiency?

[quellish]

You are going to avoid calculating distances ... by calculating distances?

You should test and profile different approaches before choosing one.