> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wherobots.com/llms.txt
> Use this file to discover all available pages before exploring further.

# RS_Resample

Resamples a raster using a given resampling algorithm and new dimensions (width and height), a new grid corner to pivot the raster at (gridX and gridY) and a set of
georeferencing attributes (scaleX and scaleY).

RS\_Resample also provides an option to pass a reference raster to draw the georeferencing attributes out of. However, the SRIDs of the input and reference raster must be same, otherwise RS\_Resample throws an IllegalArgumentException.

For the purpose of resampling, width-height pair and scaleX-scaleY pair are mutually exclusive, meaning any one of them can be used at a time.

The `useScale` parameter controls whether to use width-height or scaleX-scaleY. If `useScale` is false, the provided `widthOrScale` and `heightOrScale` values will be floored to integers and considered as width and height respectively (floating point width and height are not allowed). Otherwise, they are considered as scaleX and scaleY respectively.

Currently, RS\_Resample does not support skewed rasters, and hence even if a skewed reference raster is provided, its skew values are ignored. If the input raster is skewed, the output raster geometry and interpolation may be incorrect.

The default algorithm used for resampling is `NearestNeighbor`, and hence if a null, empty or invalid value of algorithm is provided, RS\_Resample defaults to using `NearestNeighbor`. However, the algorithm parameter is non-optional.

Following are valid values for the algorithm parameter (Case-insensitive):

1. NearestNeighbor
2. Bilinear
3. Bicubic

<Tip>
  If you just want to resize or rescale an input raster, you can use RS\_Resample(raster: Raster, widthOrScale: Double, heightOrScale: Double, useScale: Boolean, algorithm: String)
</Tip>

For more information about ScaleX, ScaleY, SkewX, SkewY, please refer to the [Affine Transformations](/reference/wherobots-db/raster-data/raster-affine-transformation) section.

<img src="https://mintcdn.com/wherobots/AayJA2u8CknIeTgt/images/sql-functions/RS_Resample/RS_Resample.svg?fit=max&auto=format&n=AayJA2u8CknIeTgt&q=85&s=baea0955114225f3ce9fcadc2e02bdfe" alt="RS_Resample" width="920" height="1120" data-path="images/sql-functions/RS_Resample/RS_Resample.svg" />

## Signatures

```sql theme={"system"}
RS_Resample(raster: Raster, widthOrScale: Double, heightOrScale: Double, gridX: Double, gridY: Double, useScale: Boolean, algorithm: String)
```

```sql theme={"system"}
RS_Resample(raster: Raster, widthOrScale: Double, heightOrScale: Double, useScale: Boolean, algorithm: String)
```

```sql theme={"system"}
RS_Resample(raster: Raster, referenceRaster: Raster, useScale: Boolean, algorithm: String)
```

## Parameters

<ParamField body="raster" type="Raster" required>
  The input raster.
</ParamField>

<ParamField body="widthOrScale" type="Double">
  The width or scale value.
</ParamField>

<ParamField body="heightOrScale" type="Double">
  The height or scale value.
</ParamField>

<ParamField body="gridX" type="Double">
  The grid x value.
</ParamField>

<ParamField body="gridY" type="Double">
  The grid y value.
</ParamField>

<ParamField body="useScale" type="Boolean" required>
  The use scale value.
</ParamField>

<ParamField body="algorithm" type="String" required>
  The algorithm value.
</ParamField>

<ParamField body="referenceRaster" type="Raster">
  The reference raster value.
</ParamField>

## Return type

<ResponseField type="Raster">
  The resulting raster.
</ResponseField>

## Examples

```sql theme={"system"}
WITH INPUT_RASTER AS (
 SELECT RS_AddBandFromArray(
    RS_MakeEmptyRaster(1, 'd', 4, 3, 0, 0, 2, -2, 0, 0, 0),
    ARRAY(1, 2, 3, 5, 4, 5, 6, 9, 7, 8, 9, 10), 1, null) as rast
),
RESAMPLED_RASTER AS (
 SELECT RS_Resample(rast, 6, 5, 1, -1, false, null) as resample_rast from INPUT_RASTER
)
SELECT RS_AsMatrix(resample_rast) as rast_matrix, RS_Metadata(resample_rast) as rast_metadata from RESAMPLED_RASTER
```

```sql theme={"system"}
| 1.0   1.0   2.0   3.0   3.0   5.0|
| 1.0   1.0   2.0   3.0   3.0   5.0|
| 4.0   4.0   5.0   6.0   6.0   9.0|
| 7.0   7.0   8.0   9.0   9.0  10.0|
| 7.0   7.0   8.0   9.0   9.0  10.0|

(-0.33333333333333326,0.19999999999999996,6,5,1.388888888888889,-1.24,0,0,0,1)
```

```sql theme={"system"}
 WITH INPUT_RASTER AS (
   SELECT RS_AddBandFromArray(
    RS_MakeEmptyRaster(1, 'd', 4, 3, 0, 0, 2, -2, 0, 0, 0),
    ARRAY(1, 2, 3, 5, 4, 5, 6, 9, 7, 8, 9, 10), 1, null) as rast
   ),
   RESAMPLED_RASTER AS (
    SELECT RS_Resample(rast, 1.2, -1.4, true, null) as resample_rast from INPUT_RASTER
   )
SELECT RS_AsMatrix(resample_rast) as rast_matrix, RS_Metadata(resample_rast) as rast_metadata from RESAMPLED_RASTER
```

```sql theme={"system"}
|       NaN         NaN         NaN         NaN         NaN         NaN         NaN|
|       NaN    3.050000    3.650000    4.250000    5.160000    6.690000    7.200000|
|       NaN    5.150000    5.750000    6.350000    7.250000    8.750000    9.250000|
|       NaN    7.250000    7.850000    8.450000    9.070000    9.730000    9.950000|
|       NaN    7.400000    8.000000    8.600000    9.200000    9.800000   10.000000|

(0.0, 0.0, 7.0, 5.0, 1.2, -1.4, 0.0, 0.0, 0.0, 1.0)
```

```sql theme={"system"}
WITH INPUT_RASTER AS (
    SELECT RS_AddBandFromArray(RS_MakeEmptyRaster(1, 'd', 4, 3, 0, 0, 2, -2, 0, 0, 0), ARRAY(1, 2, 3, 5, 4, 5, 6, 9, 7, 8, 9, 10), 1, null) as rast
),
REF_RASTER AS (
    SELECT RS_MakeEmptyRaster(2, 'd', 6, 5, 1, -1, 1.2, -1.4, 0, 0, 0) as ref_rast
),
RESAMPLED_RASTER AS (
    SELECT RS_Resample(rast, ref_rast, true, null) as resample_rast from INPUT_RASTER, REF_RASTER
)
SELECT RS_AsMatrix(resample_rast) as rast_matrix, RS_Metadata(resample_rast) as rast_metadata from RESAMPLED_RASTER
```

```sql theme={"system"}
| 1.0   1.0   2.0   3.0   3.0   5.0   5.0|
| 1.0   1.0   2.0   3.0   3.0   5.0   5.0|
| 4.0   4.0   5.0   6.0   6.0   9.0   9.0|
| 7.0   7.0   8.0   9.0   9.0  10.0  10.0|
| 7.0   7.0   8.0   9.0   9.0  10.0  10.0|

(-0.20000000298023224, 0.4000000059604645, 7.0, 5.0, 1.2, -1.4, 0.0, 0.0, 0.0, 1.0)
```