Transforming Geospatial Data

You can use the following statements, expressions, and functions to transform your geospatial records.

Comparison and Conversion Expressions

You can:

• Compare geospatial records with matching geospatial data types, such as when both records are of geospatial type point.
• Construct records in geospatial data types, such as point , lineString, and polygon by taking their coordinates as inputs. For more information, see GIS-POINT and other functions in this list that allow constructing geospatial record types.
• Calculate the area or the perimeter.

You can run the following comparison operations in Tamr on geospatial data:

• EQUALITY
• IS (NOT) NULL/EMPTY
• hash
• Conversion functions.

For a complete list of supported functions, see GIS Functions.

Examples

The following examples show some of the statements you can use on records with geospatial data types.

Note: In this list, geo* denotes one of the geospatial data types supported in Tamr.

SELECT <geo*> as <myColumn>
GROUP BY <geo*>
GROUP min(<geo*>) as min, max(<geo*>) as max
GROUP top(<geo*>, 5) as <value> by …
WINDOW for all the the GROUP BY cases
WINDOW … ORDER BY <geo*> RANGE/ROWS …
MERGE BY <geo*>
FILTER <geo*> IS (NOT) NULL/EMPTY
ORDER BY <geo*> ASC/DESC NULLS FIRST/LAST
LEFT/RIGHT/OUTER/INNER JOIN WITH <myTable> ON <geo*> = table.<geo*>
PARTITION BY <geo*>