Subject: Re: [Geojson] One nit WRT CRS clarification.

From: Carl Reed <[email-masked]>
Date: Sun, 17 Apr 2016 15:58:46 -0600

Sean -

Something to consider and can be viewed as a simple addition. The standards
CAP, geouri and open geosms all specify WGS 84 (4326) as the default CRS.
Very much the same as GeoJSON. However, these standards do add some
additional clarification WRT the use of lat/long (long/lat) coordinates. In
the case of Open GeoSMS, the following normative guidance is specified:

"Coordinates SHALL be described using the decimal degree format without the
“°”symbol. The values of latitude and longitude SHALL be bounded by ±90°
and ±180° respectively. Positive latitudes are north of the equator,
negative latitudes are south of the equator. Positive longitudes are east
of the Prime Meridian; negative longitudes are west of the Prime Meridian.
Latitude and longitude are expressed in that sequence, namely latitude
before longitude. For example, the location parameter may be shown as
“geo=23.9572,120.6860” where 23.9572 is the latitude and 120.6860 is the
longitude."

For GeoJSON, lat/long order would be switched. The reason for the
additional clarification for all three standards has already been expressed
in discussions in this WG: Many developers have little or no idea of what
WGS 84 is or means. So clear guidance is required. Believe it or not I have
seen encodings with longitudes greater than 180 degrees. Go figure :-) And
there is also the issue of some countries in the southern hemisphere
reversing the sign for latitude.

Thanks

Carl

-- 
Carl Reed, PhD
Carl Reed and Associates

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