crankshaft/doc/14_densify.md
2016-08-09 12:09:19 -04:00

36 lines
1.2 KiB
Markdown

## Densify function
Iterative densification of a set of scattered points using Delaunay triangulation. The new points are located at the centroids of the grid cells and have as assigned value the barycentric average value of the cell's vertex.
### CDB_Densify(geomin geometry[], colin numeric[], iterations integer)
#### Arguments
| Name | Type | Description |
|------|------|-------------|
| geomin | geometry[] | Array of points geometries |
| colin | numeric[] | Array of points' values |
| iterations | integer | Number of iterations |
### Returns
Returns a table object
| Name | Type | Description |
|------|------|-------------|
| geomout | geometry | Geometries of new dataset of points|
| colout | numeric | Values of points|
#### Example Usage
```sql
with data as (
select
ARRAY[7.0,8.0,1.0,2.0,3.0,5.0,6.0,4.0] as colin,
ARRAY[ST_GeomFromText('POINT(2.1744 41.4036)'),ST_GeomFromText('POINT(2.1228 41.3809)'),ST_GeomFromText('POINT(2.1511 41.3742)'),ST_GeomFromText('POINT(2.1528 41.4136)'),ST_GeomFromText('POINT(2.165 41.3917)'),ST_GeomFromText('POINT(2.1498 41.3713)'),ST_GeomFromText('POINT(2.1533 41.3683)'),ST_GeomFromText('POINT(2.131386 41.413998)')] as geomin
)
select CDB_Densify(geomin, colin, 2) from data;
```