Databases
StackOverflow2013
Postsdbo
POHow to use MySQL geospatial extensions with spherical geometries
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to use MySQL geospatial extensions with spherical geometries
    primarykey
    data
    text
    <p>I would like to store thousands of latitude/longitude points in a MySQL db. I was successful at setting up the tables and adding the data using the geospatial extensions where the column 'coord' is a Point(lat, lng). </p> <p>Problem:</p> <p>I want to quickly find the 'N' closest entries to latitude 'X' degrees and longitude 'Y' degrees. Since the Distance() function has not yet been implemented, I used GLength() function to calculate the distance between (X,Y) and each of the entries, sorting by ascending distance, and limiting to 'N' results. The problem is that this is not calculating shortest distance with spherical geometry. Which means if Y = 179.9 degrees, the list of closest entries will only include longitudes of starting at 179.9 and decreasing even though closer entries exist with longitudes increasing from -179.9. </p> <p>How does one typically handle the discontinuity in longitude when working with spherical geometries in databases? There has to be an easy solution to this, but I must just be searching for the wrong thing because I have not found anything helpful.</p> <p>Should I just forget the GLength() function and create my own function for calculating angular separation? If I do this, will it still be fast and take advantage of the geospatial extensions?</p> <p>Thanks!</p> <p>josh</p> <hr> <p><strong>UPDATE:</strong></p> <p><a href="http://jasonfollas.com/blog/archive/2008/05/16/sql-server-2008-spatial-data-part-7.aspx" rel="nofollow">This</a> is exactly what I am describing above. However, it is only for SQL Server. Apparently SQL Server has a Geometry <strong>and</strong> Geography datatypes. The geography does exactly what I need. Is there something similar in MySQL?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USJoshua
    1. USJoshua
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to use MySQL geospatial extensions with spherical geometries
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POHow to use MySQL geospatial extensions with spherical geometries
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POHow to use MySQL geospatial extensions with spherical geometries
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload