Posted on 2014-09-15
Medium Priority
Last Modified: 2014-09-15

How do I add, and substract 1 mile for a given latitude? And 1 mile to a given longitude?

Question by:SimpleDude
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
  • 2
LVL 27

Expert Comment

ID: 40323401
Latitude is easy.  Longitude is more complicated.

LVL 84

Accepted Solution

ozo earned 1600 total points
ID: 40323405
latitude + 0.014457
longitude + 0.014481/cos(latitude)
LVL 27

Assisted Solution

d-glitch earned 400 total points
ID: 40323417
And you need to be careful at the boundaries:  the N and S poles, the equator, the prime (0 deg) meridian and its opposite (180 deg).
Monthly Recap

May was a big month for new releases from Linux Academy! Take a look at what our team built recently in our blog. You can access the newest releases from our blog.


Author Comment

ID: 40323426
Hi guys, I just need to select X number of records within a Lat and Long range.

I was using this formula, but it drastically decreases the server performance:

  (ACOS(SIN(47.988594 * PI() / 180) * SIN(dbo.ADDRESSES.latitude * PI() / 180) + COS(47.988594 * PI() / 180) * COS(dbo.ADDRESSES.latitude * PI()
                      / 180) * COS((- 122.201789 - dbo.ADDRESSES.longitude) * PI() / 180)) * 180 / PI() * 60 * 1.1515 BETWEEN 0 AND @distance
LVL 27

Expert Comment

ID: 40323453
How big is the data base?  Is it sorted in any way?
What units are used in the database?  Degrees or radians?
You should search in the same units the data base uses.  Save a lot on conversions.

This   (SIN(47.988594 * PI() / 180)  (and several similar terms) are constants.  
You only have to calculate them once.

Is this related to the nearest k restaurants problem?

Author Comment

ID: 40323466
Something like that. The point of origin (lat-long) changes constantly, that's why I cannot calculate it just once.
LVL 84

Expert Comment

ID: 40323474
If the restaurants are in a small area, it may be preferable to convert the latitudes and longitudes into a flat grid to make distance calculations easier.
If the restaurants are in a large area where a flat approximation would be inaccurate, it may be preferable to convert into a 3-d orthogonal coordinate system to make distance calculations easier.

Author Closing Comment

ID: 40323557
Thanks guys

Featured Post

NFR key for Veeam Agent for Linux

Veeam is happy to provide a free NFR license for one year.  It allows for the non‑production use and valid for five workstations and two servers. Veeam Agent for Linux is a simple backup tool for your Linux installations, both on‑premises and in the public cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
When we purchase storage, we typically are advertised storage of 500GB, 1TB, 2TB and so on. However, when you actually install it into your computer, your 500GB HDD will actually show up as 465GB. Why? It has to do with the way people and computers…
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…
Suggested Courses

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question