Common Query Language (CQL)¶
This document describes the basic syntax of the common query language. CQL is the query language defined the Catalogue Service specification (CSW). CQL support in EOxServer is realized using the external pycql package.
This document is based upon the (E)CQL documentation of GeoServer with adapations wherever needed.
Syntax Specification¶
This chapter shows the syntax to define CQL queries.
Condition¶
Syntax | Description |
---|---|
Predicate | A single predicate expression |
Condition AND | OR Condition |
Logical combination of two conditions |
NOT Condition |
Logical inversion of a condition. |
( | [ Condition ] | ) |
Grouping of conditions regarding evaluation order |
Predicate¶
Syntax | Description |
---|---|
Expression = | <> | < | <=
| > | >= Expression |
Comparison of two expression |
Expression [ NOT ] BETWEEN
Expression AND Expression |
Value range Comparison |
Expression [ NOT ] LIKE | ILIKE
pattern |
Check whether an expression matches a pattern. The
% character can be used as a wildcard. |
Expression [ NOT ] IN (
Expression { , Expression ) |
Tests the inclusion of a value in a set of values. |
Expression IS [ NOT ] NULL |
Tests whether the evaluated expression is NULL |
Expression BEFORE Timestamp |
|
Expression BEFORE OR DURING
Period |
|
Expression DURING Period |
|
Expression DURING OR AFTER
Period |
|
Expression AFTER Timestamp |
|
INTERSECTS ( Expression ,
Expression ) |
|
DISJOINT ( Expression ,
Expression ) |
|
CONTAINS ( Expression ,
Expression ) |
|
WITHIN ( Expression ,
Expression ) |
|
TOUCHES ( Expression ,
Expression ) |
|
CROSSES ( Expression ,
Expression ) |
|
OVERLAPS ( Expression ,
Expression ) |
|
EQUALS ( Expression ,
Expression ) |
|
RELATE ( Expression ,
Expression , pattern ) |
|
DWITHIN ( Expression ,
Expression , Number , units
) |
|
BEYOND ( Expression ,
Expression , Number , units
) |
|
BBOX ( Expression ,
Number , Number ,
Number , Number [ , CRS ] ) |
Expression¶
Syntax | Description |
---|---|
Attribute | Name of an objects attribute |
Literal | A literal value |
Expression + | - | * | /
Expression |
Arithmetic operations of two expressions |
( | [ Expression ] | ) |
Grouping of expression regarding evaluation order |
Literal¶
Syntax | Description |
---|---|
Number |
A literal number (either floating point or integer |
Boolean |
A literal booelan value: either TRUE or FALSE |
Timestamp |
A timestamp literal. Must be in ISO 8601 compliant datetime format. |
Duration |
A timestamp literal. Must be in ISO 8601 compliant duration format. |
Geometry |
A Geometry in WKT format. EPSG:4326 is assumed |
Period¶
Syntax | Description |
---|---|
Timestamp / Timestamp |
Period definition using the start and end timestamp. |
Timestamp / Duration |
Period definition using the start timestamp and a duration afterwards. |
Duration / Timestamp |
Period definition using the end timestamp and a duration before. |
Attribute¶
Depending on the current query context, the following attributes are available to use in the queries.
Attribute name | Field type | Availability |
---|---|---|
identifier | String | All |
beginTime | Timestamp | All |
endTime | Timestamp | All |
footprint | String | All |
inserted | Timestamp | All |
updated | Timestamp | All |
productType | String | Collection |
doi | String | Collection |
platform | String | Collection |
platformSerialIdentifier | String | Collection |
instrument | String | Collection |
sensorType | String | Collection |
compositeType | String | Collection |
processingLevel | String | Collection |
orbitType | String | Collection |
spectralRange | String | Collection |
wavelength | Number | Collection |
parentIdentifier | String | Product |
productionStatus | String | Product |
acquisitionType | String | Product |
orbitNumber | Number | Product |
orbitDirection | Number | Product |
track | Number | Product |
frame | Number | Product |
swathIdentifier | String | Product |
productVersion | String | Product |
productQualityStatus | String | Product |
productQualityDegradationTag | String | Product |
processorName | String | Product |
processingCenter | String | Product |
creationDate | Timestamp | Product |
modificationDate | Timestamp | Product |
processingDate | Timestamp | Product |
sensorMode | String | Product |
archivingCenter | String | Product |
processingMode | String | Product |
availabilityTime | Timestamp | Product |
acquisitionStation | String | Product |
acquisitionSubType | String | Product |
startTimeFromAscendingNode | Number | Product |
completionTimeFromAscendingNode | Number | Product |
illuminationAzimuthAngle | Number | Product |
illuminationZenithAngle | Number | Product |
illuminationElevationAngle | Number | Product |
polarisationMode | String | Product |
polarizationChannels | String | Product |
antennaLookDirection | String | Product |
minimumIncidenceAngle | Number | Product |
maximuIncidenceAngle | Number | Product |
dopplerFrequency | Number | Product |
incidenceAngleVariation | Number | Product |
cloudCover | Number | Product |
snowCover | Number | Product |
lowestLocation | Number | Product |
highestLocation | Number | Product |