Hi ,
We plan to use GeoJSON API
and REST as our service interface. Howerver, I found that
the GeoJSON REST way doesn’t support temporal query keywords
such as “during”, right? Anybody know why GeoJSON API
doesn’t provide this part?
So our solution is to add
some temporal query funcitons in the class of
“GeoJsonQuery” to make full use of Z3 index , the code
segment looks like below:
private def evaluatePredicate(prop: String, json: JObject): GeoJsonQuery = {
println(json.obj.headOption)
json.obj.headOption match {
case Some(("$bbox", v: JArray)) =>
// { "$bbox" : [-180, -90, 180, 90] }
val List(xmin, ymin, xmax, ymax) = v.values.asInstanceOf[List[Number]]
Bbox(prop, xmin.doubleValue, ymin.doubleValue, xmax.doubleValue, ymax.doubleValue)
case Some(("$during", v)) =>
// { "$during" : "2014-01-01T00:00:00.000Z/2014-01-01T07:59:59.000Z" }
During(prop,v.values)
case Some(("$intersects", v: JObject)) =>
// { "$intersects" : { "$geometry" : { "type" : "Point", "coordinates" : [30, 10] } } }
Intersects(prop, evaluateGeometry(v))
…...
case None =>
throw new IllegalArgumentException("Invalid json structure")
}
}
//…
/**
* Temporal Duration
*
* @param prop property to evaluate
* @param value value to compare with property value
*/
case class During(prop: String, value: Any) extends GeoJsonQuery{
override def toFilter(propertyTransformer: PropertyTransformer): Filter = {
ECQL.toFilter("dtg DURING "+ff.literal(value).toString.replace("\"",""))
}
override def toString = s"""{"$prop":${printJson(value)}}"""
}
Then we can do the
spatiotempral queries like this:
curl 'localhost/geoserver/geomesa/geojson/index/tdrive_ds/tdrive_index/features' --get --data-urlencode 'q={"properties.num":"1007","geometry":{"$bbox":[116.3398,39.8407,116.34,39.8409]},"dtg":{"$during" : "2008-02-02T08:00:00Z/2008-02-02T10:00:00Z"}}'
I am wondering if anybody
can give me some suggestions if this approach is OK. If yes
I plan to add more temporal funtions to GeoJsonQuery in
order to enhance the temporal query capabilities.
Best regards,
Phil
