ST_ColorTable语法、参数和示例_云数据库 RDS(RDS)-阿里云帮助中心

获取raster对象的某一个波段的颜色表信息，返回颜色表的JSON格式。

语法

text ST_ColorTable(raster raster_obj, integer band);

参数

参数名称	描述
raster_obj	raster对象。
band	指定的波段序号，从0开始。

描述

颜色表的JSON格式：

4分量：

'{"compsCount":4,
    "entries":[
        {"value":0,"c1":0,"c2":0,"c3":0,"c4":255},
        {"value":1,"c1":0,"c2":0,"c3":85,"c4":255},
        {"value":2,"c1":0,"c2":0,"c3":170,"c4":255}
    ]
}'

3分量：

'{"compsCount":3,
    "entries":[
        {"value":0,"c1":0,"c2":0,"c3":0},
        {"value":1,"c1":0,"c2":0,"c3":85},
        {"value":2,"c1":0,"c2":0,"c3":170}
    ]
}'

如果不存在颜色表，函数返回空值。

示例

select ST_ColorTable(raster_obj,0) from raster_table where id = 1;

__________________________________
'{"compsCount":3,
    "entries":
    [
        {"value":0,"c1":0,"c2":0,"c3":0},
        {"value":1,"c1":0,"c2":0,"c3":85},
        {"value":2,"c1":0,"c2":0,"c3":170}
    ]
}'