Bounding the BQ queries in an efficient way

[rosswhitaker]

Need to investigate the tradeoff between computation on the BQ side and reporting records. Right now we reduce everything to lat-lon boxes in order to make queries computationally efficient. However,

• could do an ellipse in lat/lon around the point using something like this

WHERE SQRT(POW(Latitude - @lat, 2) + POW(Longitude - @lon, 2)) <= @radius
    AND time > @start_date AND time < @end_date
    ORDER BY time ASC

• Also could do this by spherical coordinates on the earth -- however we use a lat-lon box to save compute time on the BigQuery server

• The right way to do it is to compute a radius in spherical coordinates on the earth's surface in kms.

[rosswhitaker]

What's with the formatting on the text around this issue?

[0leks]

@rosswhitaker markdown interprets # to make it title text of various sizes

title1

title2

etc