jiayuasu commented on code in PR #1014:
URL: https://github.com/apache/sedona/pull/1014#discussion_r1322280702
##########
common/src/test/java/org/apache/sedona/common/raster/RasterTestBase.java:
##########
@@ -50,13 +51,17 @@ public class RasterTestBase {
GridCoverage2D multiBandRaster;
byte[] geoTiff;
+ private final PrintStream standardOut = System.out;
+ private final ByteArrayOutputStream outputStreamCaptor = new
ByteArrayOutputStream();
+
@Before
public void setup() throws IOException {
oneBandRaster =
RasterConstructors.fromArcInfoAsciiGrid(arc.getBytes(StandardCharsets.UTF_8));
multiBandRaster = createMultibandRaster();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
new GeoTiffWriter(bos).write(multiBandRaster, new
GeneralParameterValue[]{});
geoTiff = bos.toByteArray();
+ //System.setOut(new PrintStream(outputStreamCaptor));
Review Comment:
This comment should be removed.
##########
common/src/main/java/org/apache/sedona/common/raster/RasterOutputs.java:
##########
@@ -132,4 +132,70 @@ public static String asBase64(GridCoverage2D raster)
throws IOException {
ImageIO.write(renderedImage, "png", out);
return Base64.getEncoder().encodeToString(out.toByteArray());
}
+
+ public static String asMatrix(GridCoverage2D raster, int band, int
postDecimalPrecision) {
+ RasterUtils.ensureBand(raster, band);
+ Raster rasterData = RasterUtils.getRaster(raster.getRenderedImage());
+ int dataTypeCode = rasterData.getDataBuffer().getDataType();
+ int width = rasterData.getWidth(), height = rasterData.getHeight();
+ if (RasterUtils.isDataTypeIntegral(dataTypeCode)) {
+ int[] bandValues = rasterData.getSamples(0, 0, width, height, band
- 1, (int[]) null);
+ return createPaddedMatrixStringFromInt(bandValues, width, height,
postDecimalPrecision);
+ }else {
+ double[] bandValues = rasterData.getSamples(0, 0, width, height,
band - 1, (double[]) null);
+ return createPaddedMatrixStringFromDouble(bandValues, width,
height, postDecimalPrecision);
+ }
+ }
+
+ public static String asMatrix(GridCoverage2D raster, int band) {
+ return asMatrix(raster, band, 6);
+ }
+
+
+ public static String asMatrix(GridCoverage2D raster) {
+ return asMatrix(raster, 1);
+ }
+
+ private static String createPaddedMatrixStringFromDouble(double[] values,
int width, int height, int decimalPrecision) {
+ StringBuilder res = new StringBuilder();
+ int maxColWidth = 0;
+ int maxDecimalPrecision = 0;
+ for (double value : values) {
+ String[] splitByDecimal = String.valueOf(value).split("\\.");
+ int preDecimal = splitByDecimal[0].length(), postDecimal =
Math.min(decimalPrecision, splitByDecimal[1].length());
+ maxDecimalPrecision = Math.max(maxDecimalPrecision, postDecimal);
+ int currWidth = preDecimal + postDecimal + 1; //add 1 for space
occupied for decimal point
+ maxColWidth = Math.max(maxColWidth, currWidth);
+ }
+ for (int i = 0; i < values.length; i++) {
+ int row= i / width, col = i % width;
+ String fmt = String.format("%s%%%d.%df%s",
+ col == 0 ? "|" : " ",
+ maxColWidth,
+ maxDecimalPrecision,
+ col < width - 1 ? "" : "|%n");
+ res.append(String.format(fmt, values[i]));
+ }
+
+ return res.toString();
+ }
+
+ private static String createPaddedMatrixStringFromInt(int[] values, int
width, int height, int decimalPrecision) {
Review Comment:
Since the decimalPrecision is not used in this function, why not remove it?
##########
common/src/main/java/org/apache/sedona/common/utils/RasterUtils.java:
##########
@@ -347,4 +348,19 @@ public static int getDataTypeCode(String s) {
}
return 5; // defaulting to double
}
+
+ public static boolean isDataTypeIntegral(int dataTypeCode) {
+ //returns true if the datatype code refers to an int-like datatype
(int, short, etc)
+ switch (dataTypeCode) {
+ case 3: //int
Review Comment:
I suspect this logic will fail when you give short or byte. Can you try to
add test cases for shorts/byte?
##########
common/src/main/java/org/apache/sedona/common/Constants/RasterConstants.java:
##########
@@ -0,0 +1,6 @@
+package org.apache.sedona.common.Constants;
+
+public class RasterConstants {
+
+ public static final String INVALID_BAND = "Provided band index %d is not
present in the raster";
Review Comment:
I don't think we need the centralized place for error message for now.
Usually such a centralize place is for global parameters or hard-coded values.
##########
docs/api/sql/Raster-visualizer.md:
##########
@@ -0,0 +1,65 @@
+Sedona offers some APIs to aid in easy visualization of a raster object. Some
of these APIs might be specifically for Jupyter users and will not work in SQL.
Such APIs will have a note explicitly mentioning compatibility.
+
+## Visualize raster using base64 viewers
+
+Introduction: Returns a base64 encoded string of the given raster. This
function internally takes the first 4 bands as RGBA, and converts them to the
PNG format, finally produces a base64 string. To visualize other bands, please
use it together with `RS_Band`. You can take the resulting base64 string in [an
online viewer](https://base64-viewer.onrender.com/) to check how the image
looks like.
+
+Since: `v1.5.0`
+
+Format: `RS_AsBase64(raster: Raster)`
+
+Spark SQL Example:
+
+```sql
+SELECT RS_AsBase64(raster) from rasters
+```
+
+Output:
+
+```
+iVBORw0KGgoAAAA...
+```
+
+## Visualize a Raster band as a 2D matrix
+
+Introduction: Returns a string, that when printed, outputs the raster band as
a pretty printed 2D matrix. All the values of the raster are cast to double for
the string. RS_AsMatrix allows specifying the number of digits to be considered
after the decimal point.
+RS_AsMatrix expects a raster, and optionally a band (default: 1) and
postDecimalPrecision (default: 6). The band parameter is 1-indexed.
+
+!!!Note
+ If the provided band is not present in the raster, RS_AsMatrix throws an
IllegalArgumentException
+
+!!!Note
+ If the provided raster has integral values, postDecimalPrecision (if any)
is simply ignored and integers are printed in the resultant string
+
+Since: `1.5.0`
+
+Format: `RS_AsMatrix(raster: Raster, band: Int = 1, postDecimalPrecision: Int
= 6)`
+
+SQL Example:
+
+```scala
+val inputDf = Seq(Seq(1, 3.333333, 4, 0.0001, 2.2222, 9, 10, 11.11111111, 3,
4, 5, 6)).toDF("band")
+inputDf.selectExpr("RS_AsMatrix(RS_AddBandFromArray(RS_MakeEmptyRaster(1, 'd',
4, 3, 0, 0, 1, -1, 0, 0, 0), band, 1, 0))").show()
Review Comment:
The examples should be pure SQL example
##########
docs/api/sql/Raster-visualizer.md:
##########
@@ -0,0 +1,65 @@
+Sedona offers some APIs to aid in easy visualization of a raster object. Some
of these APIs might be specifically for Jupyter users and will not work in SQL.
Such APIs will have a note explicitly mentioning compatibility.
+
+## Visualize raster using base64 viewers
+
+Introduction: Returns a base64 encoded string of the given raster. This
function internally takes the first 4 bands as RGBA, and converts them to the
PNG format, finally produces a base64 string. To visualize other bands, please
use it together with `RS_Band`. You can take the resulting base64 string in [an
online viewer](https://base64-viewer.onrender.com/) to check how the image
looks like.
+
+Since: `v1.5.0`
+
+Format: `RS_AsBase64(raster: Raster)`
+
+Spark SQL Example:
+
+```sql
+SELECT RS_AsBase64(raster) from rasters
+```
+
+Output:
+
+```
+iVBORw0KGgoAAAA...
+```
+
+## Visualize a Raster band as a 2D matrix
+
+Introduction: Returns a string, that when printed, outputs the raster band as
a pretty printed 2D matrix. All the values of the raster are cast to double for
the string. RS_AsMatrix allows specifying the number of digits to be considered
after the decimal point.
+RS_AsMatrix expects a raster, and optionally a band (default: 1) and
postDecimalPrecision (default: 6). The band parameter is 1-indexed.
+
+!!!Note
+ If the provided band is not present in the raster, RS_AsMatrix throws an
IllegalArgumentException
+
+!!!Note
+ If the provided raster has integral values, postDecimalPrecision (if any)
is simply ignored and integers are printed in the resultant string
+
+Since: `1.5.0`
+
+Format: `RS_AsMatrix(raster: Raster, band: Int = 1, postDecimalPrecision: Int
= 6)`
+
+SQL Example:
+
+```scala
+val inputDf = Seq(Seq(1, 3.333333, 4, 0.0001, 2.2222, 9, 10, 11.11111111, 3,
4, 5, 6)).toDF("band")
+inputDf.selectExpr("RS_AsMatrix(RS_AddBandFromArray(RS_MakeEmptyRaster(1, 'd',
4, 3, 0, 0, 1, -1, 0, 0, 0), band, 1, 0))").show()
+```
+
+Output:
+```sql
+| 1.00000 3.33333 4.00000 0.00010|
+| 2.22220 9.00000 10.00000 11.11111|
+| 3.00000 4.00000 5.00000 6.00000|
+```
+
+SQL Example:
+
+```scala
+val inputDf = Seq(Seq(1, 3, 4, 0, 2, 9, 10, 11, 3, 4, 5, 6)).toDF("band")
Review Comment:
The examples should be pure SQL example
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