How accurate is coordinates JSON field?


#1

Hi folks,

I know there have been tons of questions about this field, but I just wanted to check that I’m right. I’ve a load of tweets that I’m parsing. They have something like this field:

“bounding_box”:
{
“type”:“Polygon”,
“coordinates”:
[
[
[-1.2143009999999999,50.7728505],
[-1.2143009999999999,50.8402211],
[-1.1061189999999999,50.8402211],
[-1.1061189999999999,50.7728505]
]
]
},

This is the bounding box coordinates for the system, but I’m not using this, instead choosing to have a centralised location for tweets, using the coordinates field:

“coordinates”:
{
“type”:“Point”,
“coordinates”:
[-1.3,50.2]
}

This seems to make sense as this coordinate is certainly within the bounding box above. I know it is longitude first, then latitude. But when I plug it into a coordinate finder, it turns out to be in the middle of the English Channel.

The tweet in question is from GoSport, which is on the very South coast of England, just above the Isle of Wight. Therefore, the coordinates are certainly close to where they are meant to be. But they’re still a good 50 miles off.

Am I using the field in the wrong way, or do I simply have unrealistic expectations as to the accuracy of the coordinates field?