This topic describes the ST_BuildPyramid function, which builds a vector pyramid for a spatial geometry data table to expedite data display.

Syntax

boolean ST_BuildPyramid(cstring table, cstring geom, cstring fid, cstring config)

Parameters

Parameter Description
table The name of the spatial geometry table for which you want to build a pyramid.
geom The name of the geometry field.
fid The name of the element ID field.
config The fields that are used to build a pyramid. These fields are specified in a JSON-formatted string.

The following table describes the fields in the config parameter.

Field Data type Default value Description
name string Same as the table name The name of the pyramid.
parallel int 0 The maximum number of tasks that can run in parallel to build the pyramid. The value 0 indicates that the maximum number is not limited.
tileSize int 1024 The tile size of the pyramid. Valid values must be greater than 0 but less than 4096.
tileExtend int 8 The tile extension size of the pyramid. Valid values must be greater than 0.
maxLevel int 16 The maximum number of layers in the pyramid. Valid values: 0 to 20.
buildRules array[object] null The rule based on which you want to build the pyramid. Each rule consists of two parts: level and value.
└level array[int] None The pyramid layers to which the rule applies.
└value object None The value of the rule.
└filter string None The expression that is used to filter data in PostgreSQL.
└attrFields array[string] None The name of the attribute field when the MVT format is used.
└merge array[string] None The filter conditions that are used to add data records to a group.
└cull array[string] None The filter conditions that are used to remove data records from a group.

The following example shows how to configure the config parameter: 

{
   "name" : "hello",      
   "parallel": 0,         
   "tileSize": 1024,      
   "tileExtend": 8,       
   "maxLevel": 16,        
   "buildRules": [        
     {
       "level": [0,1,2],  
       "value": {
         "filter": "code! =0",               
         "attrFields": ["name","color"],    
         "merge":["code=1","code! =1"],      
         "cull" :["code=1","code! =1"]       
       }
     }
   ]
}

Examples

--Create a pyramid for the spatial geometric data table named roads.
select ST_BuildPyramid('roads', 'geom', 'id', '');
st_buildpyramid
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t