1 geo.intersection

Returns the geometry corresponding to the topological intersection of the two geometries (AND operation).

<geo.intersection ora_tol='ora_tol'>
    <geom1> *
        <geom1 /> *
    </geom1>
    <geom2> *
        <geom2 /> *
    </geom2>
</geo.intersection>

Attributes
Name	Type	Required	Default	Description
Aora_tol	decimal			0.05	Tolerance. It is only used in Oracle.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeom1
Egeom1	geometry
Egeom2
Egeom2	geometry

Example

Copy

<select>
    <columns>
       <geo.intersection>
            <geom1>geometry_col_1</geom1>
            <geom2>geometry_col_2</geom2>
       </geo.intersection>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

2 geo.buffer

Returns the geometry that represents all the points that are at a distance equal to or less than the given distance of the past geometry.

<geo.buffer
    pg_seg='pg_seg'
    ora_tol='ora_tol'
    ora_arctol='ora_arctol'
    sql_tol='sql_tol'
    sql_rel='sql_rel'
>
    <geom1> *
        <geom1 /> *
    </geom1>
    <dist> *
        <dist /> *
    </dist>
</geo.buffer>

Attributes
Name	Type	Required	Default	Description
Apg_seg	integer			8	Number of segments used to approximate a quarter circle. It is only used in Postgres.
Aora_tol	decimal			0.05	Tolerance. It is only used in Oracle.
Aora_arctol	decimal			0.05	Tolerance. It is only used in Oracle.
Asql_tol	decimal			0.05	Refers to the maximum variation in the ideal buffer distance for the returned linear approximation.
Asql_rel	decimal			0.05	Relative. Is a bit specifying whether the tolerance value is relative or absolute.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeom1
Egeom1	geometry
Edist
Edist	decimal

Example

Copy

<select>
    <columns>
       <geo.buffer>
            <geom1>geometry_col_1</geom1>
            <dist>10</dist>
       </geo.buffer>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

3 geo.simplify

It simplifies the input geometry based on the indicated threshold value. This function is useful when a geometry with less resolution is required than the original geometry. This function uses the Douglas-Peucker algorithm.

This function can change the geometry topology and can result in invalid geometries.

In Postgres the attribute pg_preserve = 'y' serves to ensure that the topology is preserved.

<geo.simplify
    pg_preserve='y|n'
    ora_tol='ora_tol'
    threshold='threshold'
>
    <geom1 /> *
</geo.simplify>

Attributes
Name	Type	Required	Default	Description
Apg_preserve	integer			n	Only used in Postgres. If pg_preserve = 'y' is indicated, the geometry tolopolgy will be preserved.
Aora_tol	decimal			0.05	Tolerance. It is only used in Oracle.
Athreshold	decimal				Gives a degree measure of geometry simplification. The higher, the greater the simplification.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeom1

Example

Copy

<select>
    <columns>
       <geo.simplify threshold='0.006'>
            <geom1>geometry_col_1</geom1>
       </geo.simplify>,
       <geo.simplify  tol='0.004' pg_preserve='y' threshold='0.006'>
            <geom1>geometry_col_1</geom1>
       </geo.simplify>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

4 geo.convexHull

Returns the minimum convex geometry that contains the geometry. It can be thought of as the geometry that is obtained when an elastic band is put around that of geometry.

<geo.convexHull ora_tol='ora_tol'>
    <geometry_column /> *
</geo.convexHull>

Attributes
Name	Type	Required	Default	Description
Aora_tol	decimal			0.05	Tolerance. It is only used in Oracle.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeometry_column

Example

Copy

<select>
    <columns>
       <geo.convexHull ora_tol='0.005'>geometry_col</geo.convexHull>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

5 geo.difference

Returns the geometry that represents the geom1 geometry that does not intersect with the geom2 geometry.

<geo.difference ora_tol='ora_tol'>
    <geom1> *
        <geom1 /> *
    </geom1>
    <geom2> *
        <geom2 /> *
    </geom2>
</geo.difference>

Attributes
Name	Type	Required	Default	Description
Aora_tol	decimal			0.05	Tolerance. It is only used in Oracle.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeom1
Egeom1	geometry
Egeom2
Egeom2	geometry

Example

Copy

<select>
    <columns>
       <geo.difference ora_tol=''>
            <geom1>geometry_col_1</geom1>
            <geom2>geometry_col_2</geom2>
       </geo.difference>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

6 geo.symDifference

Returns the geometry that represents the geometry parts of geom1 and geom2 that do not intersect. It is called symmetric because ST_SymDifference(geom1,geom2)=ST_SymDifference(geom2,geom1). It can be thought of as: ST_Union(geom1,geom2) - ST_Intersection (geom1, geom2).

<geo.symDifference ora_tol='ora_tol'>
    <geom1> *
        <geom1 /> *
    </geom1>
    <geom2> *
        <geom2 /> *
    </geom2>
</geo.symDifference>

Attributes
Name	Type	Required	Default	Description
Aora_tol	decimal			0.05	Tolerance. Only used in Oracle.

Arguments
Name	Type	Required	Unique	Nullable	Description
Egeom1
Egeom1	geometry
Egeom2
Egeom2	geometry

Example

Copy

<select>
    <columns>
       <geo.difference ora_tol=''>
            <geom1>geometry_col_1</geom1>
            <geom2>geometry_col_2</geom2>
       </geo.difference>
    </columns>
    <from table='buildings' alias='a' >
    </from>
    <where>
        a.name = 'MACBA'
    </where>
</select>

Geometry Processing Functions

1 geo.intersection

2 geo.buffer

3 geo.simplify

4 geo.convexHull

5 geo.difference

6 geo.symDifference