Event data distribution - mapserv.eventdata
Data obtained from sensors and other sources is recorded as event data.
The event data distribution API can obtain event data that matches the specified conditions.
JSON-RPC v2.0 is used as the execution method.
Request Sample
{
"jsonrpc": "2.0",
"method": "mapserv.eventdata",
"params": {
"type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": [[
[139.7, 34.9], [139.7, 36.1], [140.9, 36.1],
[140.9, 34.9], [139.7, 34.9]
]]
},
"properties": {
"table": "riskmap.riskmap_probability",
"columns": ["start_datetime", "risk"],
"conds": {
"and": [
{
">=": ["start_datetime", "2020-05-05 13:00:00"]
},
{
"<": ["end_datetime", "2020-05-05 15:00:00"]
}
]
}
}
},
"id": "mapserv_eventdata"
}
Parameter
Request parameters are described in GeoJSON Feature format.
Geometry is a spatial region to be searched for. The type can be Polygon, Line, Point, or Collection of these.
For Properties, specify the following parameters:
Parameter Name | Data Type | Details | Default Value |
---|---|---|---|
table | string | Table name of the event data | Required |
columns | [string] | List of columns to be retrieved | [] (All columns) |
conds | object | Conditions for searching records | {} (No condition) |
Output Sample
Return Values
GeoJSON (FeatureCollection) is returned. Each record of event data is stored as a Feature.
Each feature's geometry
is the GeoJSON representation of the geom.
In the properties
, the table name will be stored in table
, and the rest is stored as a set of column names and their values.
Description
The spatial and non-spatial attributes of event data can be obtained by specifying the conditions. Compared to other APIs, complex search conditions can be specified.
- Event data stored in the table specified by
table
is targeted. - The record whose
geom
column and thegeometry
part of the request intersects will be obtained. - If
columns
is specified, only the columns are returned. However, thegeom
column is always returned as a GeoJSON geometry. - If
conds
is specified, records satisfying allgeometry
andconds
conditions are returned. conds
is written in JsonLogic notation.
The available operators of JsonLogic are as follows:
- {"=":[A,B]} A is equal to B
- {"<>":[A,B]} A is not equal to B
- {">":[A,B]} A is larger than B
- {">=":[A,B]} A is larger than or equal to B
- {"<":[A,B]} A is smaller than B
- {"<=":[A,B]} A is smaller than or equal to B
- {"!":[A]} Not A
- {"and":[A,B,...]} All A,B,... are satisfied
- {"or":[A,B,...]} At least one of A,B,... is satisfied
- {"in":[A,[B]]} A is included in [B]
- {"min":[A]} The minimum value of [A]
- {"max":[A]} The maximum value of [A]
Note: A and B are column name or constants. The string constant same as the column names cannot be specified.
Very large GeoJSONs may be returned if there are many records
that meet the condition, or if the spatial attributes stored in geom
have a complex shape.