MARKLOGIC SERVER

An Advanced Trick
If you use the coordinate system "raw" in the API calls, MarkLogic treats the world as flat (as well as infinite)
and compares points simplistically without the complex great circle ellipsoid math. This comes in handy
if you ever want a two-value range index to represent something other than geography, such as a medical
patient's height and weight. Assume height represented as longitude (x-axis) and weight as latitude (y-axis).
If the data were laid out as a chart, the results from a large set of patients would look like a scatter plot.
Using MarkLogic's geospatial calls you can draw arbitrary polygons around the portions of the chart that are
meaningful—such as which patients should be considered normal, overweight, or underweight according to
different statistical measures—and use those regions as query constraints. The trick works for any data series
with two values where it makes sense to think of the data as a scatter plot and limit results by point, box,
circle, or polygon.
THE REVERSE INDEX
All of the indexing strategies we've discussed up to this point execute what you might
call forward queries, where you start with a query and find the set of matching documents.
A reverse query does the opposite: you start with a document and find all of the matching
queries (the set of stored queries that if executed would match this document).
Programmatically, you start by storing serialized representations of queries within
MarkLogic. You can store them as simple documents or as elements within larger
documents. For convenience, any cts:query object automatically serializes as XML
when placed in an XML context. This XQuery:
{
cts:and-query((
cts:word-query("dog"),
cts:element-word-query(xs:QName("name"), "Champ"),
cts:element-value-query(xs:QName("gender"), "female"))
)
}
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