如何从坐标中获取经度

Question

我有一个名为IK_TEMP的表，它包含名为data，range的列。

        String sql = "SELECT DATA, RANGE FROM IK_TEMP";

        try (Connection conn = this.connect();
             Statement stmt  = conn.createStatement();
             ResultSet rs    = stmt.executeQuery(sql)){

            // loop through the result set
            while (rs.next()) {
                System.out.println(rs.getString("DATA") +  "\t" + 
                                   rs.getString("RANGE"));
               fromBytes(rs.getBytes("RANGE"));
            }

RANGE字段（二进制/ BLOB）字段已经使用来自arcGIS的二进制文件进行了编码，并保存在数据库中。http://www.geopackage.org/spec120/#gpb_format

我想使用Java解码此RANGE字段。

[Here I have tried with fromBytes方法

public void fromBytes(byte[] bytes) {
            this.bytes = bytes;

            ByteReader reader = new ByteReader(bytes);

            // Get 2 bytes as the magic number and validate
            String magic = null;
            try {
                magic = reader.readString(2);
            } catch (UnsupportedEncodingException e) {
                throw new GeoPackageException(
                        "Unexpected GeoPackage Geometry magic number character encoding: Expected: "
                                + GeoPackageConstants.GEOMETRY_MAGIC_NUMBER);
            }
            if (!magic
                    .equals(GeoPackageConstants.GEOMETRY_MAGIC_NUMBER)) {
                throw new GeoPackageException(
                        "Unexpected GeoPackage Geometry magic number: "
                                + magic
                                + ", Expected: "
                                + GeoPackageConstants.GEOMETRY_MAGIC_NUMBER);
            }

            // Get a byte as the version and validate, value of 0 = version 1
            byte version = reader.readByte();
            if (version != GeoPackageConstants.GEOMETRY_VERSION_1) {
                throw new GeoPackageException(
                        "Unexpected GeoPackage Geometry version: "
                                + version
                                + ", Expected: "
                                + GeoPackageConstants.GEOMETRY_VERSION_1);
            }

            // Get a flags byte and then read the flag values
            byte flags = reader.readByte();
            int envelopeIndicator = readFlags(flags);
            reader.setByteOrder(byteOrder);

            // Read the 5th - 8th bytes as the srs id
            srsId = reader.readInt();

            // Read the envelope
            envelope = readEnvelope(envelopeIndicator, reader);

            // Save off where the WKB bytes start
            wkbGeometryIndex = reader.getNextByte();

            // Read the Well-Known Binary Geometry if not marked as empty
            if (!empty) {
                geometry = GeometryReader.readGeometry(reader);
            }

        }

但是问题是我在x对象中获得了y和geometry，使用此x和y我无法获得经度和纬度。

Answer 1

请尝试以下方法获取数据：

Blob picture = resultSet.getBlob("RANGE");
inputStream = picture.getBinaryStream();
outputStream = new FileOutputStream("D:\\blob\\RANGE.jpg");
byte[] bufferBytes = new byte[1024];
int len = 0;
while ((len = inputStream.read(bufferBytes)) != -1) {
    outputStream.write(bufferBytes, 0, len);
}