Point datatype is displayed in Well Known Text (WKT) format in the dataset user interface. The Well Known Text format is also used when ingressing
Point columns using certain tools, like DataSync. Example:
coordinatesproperty, GeoJSON and Well Known Text order the coordinates as "longitude, latitude" (X coordinate, Y coordinate), as other GIS coordiate systems are encoded. Note that the SoQL
within_circlefunctions use the more conventional ordering, however.
The following operators can be used on
The following table describes the functions that can be used with
||Returns distinct set of records||2.1|
||Returns different values based on the evaluation of boolean comparisons||2.1|
||Returns the minimum convex geometry that encloses all of the geometries within a set||2.1|
||Returns a count of a given set of records||2.0 and 2.1|
||Returns the distance between two Points in meters||2.1|
||Returns a bounding box that encloses a set of geometries||2.1|
||Allows you to compare two geospatial types to see if they intersect or overlap each other||2.1|
||Returns the number of vertices in a geospatial data record||2.1|
||Returns the rows that have geodata within the specified box, defined by latitude, longitude corners||2.0 and 2.1|
||Returns the rows that have locations within a specified circle, measured in meters||2.0 and 2.1|
||Returns the rows that have locations within the specified box, defined by latitude, longitude corners||2.1|
However, there are also a ton of additional geo query functions that come with the Point datatype. For example, to aggregate that same dataset by ward and return polygons surrounding each cluster, in GeoJSON:
Back in school, you were taught that points on the earth were defined as “degrees of latitude and longitude”, right? You probably used them to find locations on the globe, to locate your campsite, or to plot the location of that prime fishing spot or anchorage. So why then are locations in the
Point datatype encoded as
Well, a latitude and longitude pair, usually used on a Mercator projection is actually only one of many many different ways of translating locations on our (semi-)spherical world onto a flat piece of paper (or an LCD monitor). Not only are there dozens of ways of flattening that globe into a plane (called map projections), but there are also thousands of ways of actually mapping coordinates onto those projections.
GeoJSON and Well Known Text are designed to be flexible to work with many different map projections and coordinate projections, and just like the Cartesian coordinates you learned in math class, those coordinates are encoded in “X, Y” order. With the
EPSG:4326 coordinate system that we use for our geospatial datatypes, that means that the coordinates are encoded in
$longitude, $latitude order.
For fun, check out this excellent XKCD comic to see what your favorite map projection says about you.