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Re: [geotrellis-user] Data Missing when extracting pixel value from Raster
Hey Ashish,

So what is the question? Is it about the nature of the dots you see?
It’s a bit hard to parse your code and a bit unclear what’s the question.
However, I’m wondering, is this what you see with the scene you just loaded into the spark memory and that’s all?
Some of possible issues you’re hitting is a NoData issue - and mb you’re hitting NoData points and that’s why they are missing here.
if it’s possible, I would like to request some more details to answer the question.

Thanks,

Grigory

On Wed, Mar 27, 2019 at 8:25 AM Ashish Agarwal <ashishagarwal1983@xxxxxxxxx> wrote:
Hello We are trying to convert lzw compressed raster(tiff) into text format(meaning extracting each pixel centroid and band1 value.. We see that some parts of the raster is missed while conversion.. however there is a pattern in miss data (data is coming in unequal striped pattern) Please see snapshot attached .. Yellow dots shows the centroid converted while no overlap with yellow the data is missed while converting..

Code :- 

    List<String> tiffExtensions = new ArrayList<>();
    tiffExtensions.add(".tif");
    tiffExtensions.add(".TIF");
    tiffExtensions.add(".tiff");
    tiffExtensions.add(".TIFF");

    final scala.Option<CRS> crsNone = scala.Option.apply(null);
    final scala.Option<Object> objectNone = scala.Option.apply(null);
    final scala.Option<Object> numPartitionsObject = scala.Option.apply(new Integer(10));
    final scala.Option<Object> tileSize = scala.Option.apply(Integer.parseInt("256"));
    final scala.Option<Object> partitionBytes = scala.Option.apply(128l * 1024 * 1024);
    HadoopGeoTiffRDD.Options options = new HadoopGeoTiffRDD.Options$().apply(
            JavaConverters.asScalaIteratorConverter(tiffExtensions.iterator()).asScala().toSeq(), crsNone,
            HadoopGeoTiffRDD.GEOTIFF_TIME_TAG_DEFAULT(), HadoopGeoTiffRDD.GEOTIFF_TIME_FORMAT_DEFAULT(), tileSize,
            numPartitionsObject, partitionBytes, objectNone);
    RDD<Tuple2<ProjectedExtent, Tile>> rasterImageRdd = HadoopGeoTiffRDD.spatial(new Path(rastedImageDir), options,
            javaSparkContext.sc());
    JavaRDD<Tuple2<ProjectedExtent, Tile>> rasterImageJavaRdd = rasterImageRdd.toJavaRDD();
    JavaRDD<String> pixelRdd = rasterImageJavaRdd
            .flatMap(new FlatMapFunction<Tuple2<ProjectedExtent, Tile>, String>() {
                private static final long serialVersionUID = -6395159549445351446L;

                public Iterator<String> call(Tuple2<ProjectedExtent, Tile> v1) throws Exception {
                    ArrayList<String> list = new ArrayList<String>();
                    Tile t = v1._2;
                    ProjectedExtent projectedExtent = v1._1;
                    ProjectedRaster<CellGrid> r = new ProjectedRaster<CellGrid>(
                            new Raster<CellGrid>(t, projectedExtent.extent()), projectedExtent.crs());
                    GeometryFactory geometryFactory = new GeometryFactory(new PrecisionModel(), 4283);
                    WKTWriter wktWriter = new WKTWriter();
                    for (int i = 0; i < t.rows(); i++) {
                        for (int j = 0; j < t.cols(); j++) {
                            StringBuilder sb = new StringBuilder();
                            if (!Double.isNaN(t.getDouble(j, i))) {
                                Double elevation = t.getDouble(j, i);
                                Tuple2<Object, Object> longLatTupel = r.raster().rasterExtent().gridToMap(j, i);
                                if (longLatTupel._2() != null && longLatTupel._1() != null) {
                                    Double latitude = Double.parseDouble(longLatTupel._2() + "");
                                    Double longitude = Double.parseDouble(longLatTupel._1() + "");
                                    Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));
                                    sb.append(elevation).append(TAB_SEP);
                                    sb.append(point);
                                    list.add(sb.toString());
                                }
                            }
                        }
                    }
                    return list.iterator();
                }
            });
--
Regards
Ashish Agarwal


Ph - +91- 9711163631
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--
Grigory Pomadchin
LinkedIn: http://www.linkedin.com/in/grpomadchin

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