Wrong distance shown in miles for extension earthdistance

Started by PG Bug reporting formabout 5 years ago2 messagesdocs
Jump to latest
#1PG Bug reporting form
noreply@postgresql.org

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/earthdistance.html
Description:

Hi,
I have installed
CREATE EXTENSION CUBE;
CREATE EXTENSION earthdistance;

Post which I ran the following query:
SELECT (POINT (19.974, 72.756)<@> POINT (19.195, 72.959)) AS DISTANCE;

The answer came back as 21.17534 miles whereas the actual distance (as crow
flies) is 55.42 miles which I have checked from 2-3 websites. (Google maps
gives a greater distance which is travel by road & this value has been
ignored).

I know both the places and the distance between both of them cannot be 22
miles. It has to be in excess of 50 miles atleast. What am I missing?

#2Magnus Hagander
magnus@hagander.net
In reply to: PG Bug reporting form (#1)
Re: Wrong distance shown in miles for extension earthdistance

On Mon, Mar 22, 2021 at 9:27 AM PG Doc comments form
<noreply@postgresql.org> wrote:

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/earthdistance.html
Description:

Hi,
I have installed
CREATE EXTENSION CUBE;
CREATE EXTENSION earthdistance;

Post which I ran the following query:
SELECT (POINT (19.974, 72.756)<@> POINT (19.195, 72.959)) AS DISTANCE;

The answer came back as 21.17534 miles whereas the actual distance (as crow
flies) is 55.42 miles which I have checked from 2-3 websites. (Google maps
gives a greater distance which is travel by road & this value has been
ignored).

I know both the places and the distance between both of them cannot be 22
miles. It has to be in excess of 50 miles atleast. What am I missing?

By your queasy it looks like you are comparing two points in the Norwegian Sea.

I think you may have swapped your latitude and longitude, and are
actually looking for:

postgres=# SELECT (POINT (72.756, 19.974)<@> POINT (72.959, 19.195))
AS DISTANCE;
distance
--------------------
55.421996899143366

--
Magnus Hagander
Me: https://www.hagander.net/
Work: https://www.redpill-linpro.com/