kanchanchy commented on code in PR #612: URL: https://github.com/apache/incubator-sedona/pull/612#discussion_r853638415
########## sql/src/main/scala/org/apache/spark/sql/sedona_sql/io/GeotiffFileFormat.scala: ########## @@ -101,4 +126,123 @@ private[spark] class GeotiffFileFormat extends FileFormat with DataSourceRegiste } } } + + private def isValidGeoTiffSchema(options: Map[String, String], dataSchema: StructType): Boolean = { + val colImage = options.getOrElse("key_image", "image") + val fields = dataSchema.fieldNames + if (fields.contains(colImage) ){ + val schemaFields = dataSchema.fields(dataSchema.fieldIndex(colImage)).dataType.asInstanceOf[StructType] + if (schemaFields.fieldNames.length != 6) return false + } + else { + if (fields.length != 6) return false + } + true + } + +} + +// class for writing geoTiff images +private class GeotiffFileWriter(savePath: String, + options: Map[String, String], + dataSchema: StructType, + context: TaskAttemptContext) extends OutputWriter { + + // set writing parameters + private val DEFAULT_WRITE_PARAMS: GeoTiffWriteParams = new GeoTiffWriteParams() + DEFAULT_WRITE_PARAMS.setCompressionMode(ImageWriteParam.MODE_EXPLICIT) + DEFAULT_WRITE_PARAMS.setCompressionType("LZW") + DEFAULT_WRITE_PARAMS.setCompressionQuality(0.75F) + DEFAULT_WRITE_PARAMS.setTilingMode(ImageWriteParam.MODE_EXPLICIT) + DEFAULT_WRITE_PARAMS.setTiling(512, 512) + + private val hfs = new Path(savePath).getFileSystem(context.getConfiguration) + + override def write(row: InternalRow): Unit = { + // retrieving the metadata of a geotiff image + var rowFields: InternalRow = row + var schemaFields: StructType = dataSchema + val fields = dataSchema.fieldNames + + val colImage = options.getOrElse("key_image", "image") + val colOrigin = options.getOrElse("key_origin", "origin") + val colBands = options.getOrElse("key_n_bands", "nBands") + val colWidth = options.getOrElse("key_width", "width") + val colHeight = options.getOrElse("key_height", "height") + val colWkt = options.getOrElse("key_wkt", "wkt") + val colData = options.getOrElse("key_data", "data") + + if (fields.contains(colImage)) { + schemaFields = dataSchema.fields(dataSchema.fieldIndex(colImage)).dataType.asInstanceOf[StructType] + rowFields = row.getStruct(dataSchema.fieldIndex(colImage), 6) + } + + val tiffOrigin = rowFields.getString(schemaFields.fieldIndex(colOrigin)) + val tiffBands = rowFields.getInt(schemaFields.fieldIndex(colBands)) + val tiffWidth = rowFields.getInt(schemaFields.fieldIndex(colWidth)) + val tiffHeight = rowFields.getInt(schemaFields.fieldIndex(colHeight)) + val tiffGeometry = rowFields.getString(schemaFields.fieldIndex(colWkt)) + val tiffData = rowFields.getArray(schemaFields.fieldIndex(colData)).toDoubleArray() + + // create a writable raster object + val raster = RasterFactory.createBandedRaster(DataBuffer.TYPE_DOUBLE, tiffWidth, tiffHeight, tiffBands, null) + + // extract the pixels of the geotiff image and write to the writable raster + val pixelVal = Array.ofDim[Double](tiffBands) + for (i <- 0 until tiffHeight) { + for (j <- 0 until tiffWidth) { + for (k <- 0 until tiffBands) { + pixelVal(k) = tiffData(tiffHeight*tiffWidth*k + i * tiffWidth + j) + } + raster.setPixel(j, i, pixelVal) + } + } + + // CRS is always fixed to EPSG:4326 + val crs = CRS.decode("EPSG:4326", true) Review Comment: The CRS that we pass there, it should be the correct CRS representing the polygon of image source. So, if users transform the polygon using ST_Transform, they must need to provide the transformed CRS as writeToCRS option. Also, if we use a default CRS in the absence of writeToCRS, that default CRS should be actual CRS of the polygon. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@sedona.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org