ST_LINEFROMTEXT
Description
Converts a WKT (Well Known Text) string into an in-memory representation of a Line
Alias
- ST_LINESTRINGFROMTEXT
Sytax
ST_LINEFROMTEXT( <wkt>)
Parameters
Parameters | Description |
---|---|
<wkt> | A WKT string conforming to the LINE type, formatted as: |
"LINE (x1 y1, x2 y2)" | |
Where (x1 y1), (x2 y2) are the vertex coordinates of the line segment. Coordinate values are numeric (integers or decimals). |
Return value
Returns a geometric object of type Line, which is stored in memory in Doris's internal spatial data format. It can be directly passed as a parameter to other spatial functions (such as ST_LENGTH, ST_INTERSECTS, etc.) for calculations.
- Returns NULL if the input WKT string is invalid (e.g., fewer than 2 vertices, syntax errors, non-numeric coordinates, etc.).
- Returns NULL if
is NULL or an empty string.
Example
Normal LINE type
mysql> SELECT ST_AsText(ST_LineFromText("LINESTRING (1 1, 2 2)"));
+-----------------------------------------------------+
| ST_AsText(ST_LineFromText("LINESTRING (1 1, 2 2)")) |
+-----------------------------------------------------+
| LINESTRING (1 1, 2 2) |
+-----------------------------------------------------+
Invalid WKT (insufficient vertices)
mysql> SELECT ST_LineFromText("LINESTRING (1 1)");
+-------------------------------------+
| ST_LineFromText("LINESTRING (1 1)") |
+-------------------------------------+
| NULL |
+-------------------------------------+
Invalid WKT (syntax error)
mysql> SELECT ST_LineFromText("LINESTRING (1 1, 2 2");
+-----------------------------------------+
| ST_LineFromText("LINESTRING (1 1, 2 2") |
+-----------------------------------------+
| NULL |
+-----------------------------------------+
Invalid WKT (too many vertices)
mysql> SELECT ST_LineFromText("LINESTRING (1 1,2 2,3 3)");
+---------------------------------------------------------------------------------+
| ST_LineFromText("LINESTRING (1 1,2 2,3 3)") |
+---------------------------------------------------------------------------------+
| ��_<���?'���Xޑ?݉+
ߑ?�����?(Qjm�ۡ?'���Xޡ?�3|ʏ��?lW<�`ª?��H�˪? |
+---------------------------------------------------------------------------------+
Input NULL
mysql> SELECT ST_LineFromText(NULL);
+-----------------------+
| ST_LineFromText(NULL) |
+-----------------------+
| NULL |
+-----------------------+