1 Producing bathymetric ENCs with SevenCs ENC Tools Friedhelm Moggert-Kägeler SevenCs ENC Tools User Conference Hamburg 13 14 November 2008
Structure of Presentation Part 1 2 benc Background and Introduction Hydrographic Survey Data and ENCs. ENCs with High Density Bathymetry. Introduction of bathymetric ENC. benc and ENCs complement each other 2
Hydrographic Survey Data and ENCs 3 Most accurate bathymetric data is collected on a regular basis. However, data are not incorporated in regular ENCs. Regular ENCs contain bathymetry at low resolution only (see Example next slide). 3
Example - Depth Information in standard compliant official ENC 4 DEPARE: 11.0 36.6 Please note: We are not saying that this is an example for bad ENC data. We assume that this ENC fully complies with the relevant standards for ENC production and quality control. This is just an example showing that depth information in regular ENCs is not very dense. We could have chosen an ENC from any other agency. US5VA15M.000 Norfolk International Terminals 4
Producing ENCs with High Density Bathymetry 5 Technically the integration of high density bathymetry in ENCs is not an issue at all. The conversion process can be automated to a far extent with appropriate software tools. Digital bathymetric data in any common GIS or CAD format can be used as source data. 5
Introducing bathymetric ENCs 6 The result is a hydrographic fairsheet in S-57 format. We call it a bathymetric ENC (benc). 7Cs benc concept aims at maintaining high density depth information in separate S-57 layers. 6
Conversion Result: bathymetric ENC 7 benc with dense bathymetry In the example depth contours and depth areas are shown. Depth contours have been produced at 1m intervals 7
benc and ENCs complement each other 8 bencs provide additional complementary information not available in regular ENCs. bencs do not replace ENCs. They must be considered an additional, optional bathymetric layer for regular ENCs. A combination of both provides a complete chart image with up-to-date and detailed bathymetry. 8
benc and ENCs complement each other 9 Data of the latest survey sessions can be integrated within a couple of days or less. private organisations or companies can use their own survey data to produce bencs. 9
Chart Display ENC and bathymetric ENC 10 Harbour ENC with benc switched off...... and benc switched on 10
Chart Display ENC and bathymetric ENC 11 11
Chart Display ENC and bathymetric ENC 12 12
benc and ENCs complement each other 13 Complementary use of bencs and ENCs makes applications focussing on high precision navigation (e.g. Pilot Units) safer and more effective. 13
14 Structure of Presentation Part 2 benc Production Source Data Requirements S-57 Data Conversion benc - Finishing up benc Product Specification benc Processing Steps (3 Examples) Maintenance of bencs 14
15 Source Data Requirements 15
16 Source Data Structure, Formats, Requirements Results of Single Beam Surveys (clean data) Results of Multibeam Surveys (clean data) Modelled Data (gridded bathymetry, contour files) Format (almost) any; e.g. dxf, shape, ASCII, etc. Metadata: Coordinate System Parameters, Vertical Datum, Survey Date, etc. 16
17 S-57 Data Conversion 17
18 Data Conversion Processing of Source Data The conversion results in properly encoded S-57 depth contours (DEPCNT, VALDCO). The individual processing steps are dependend on the type of source data. Potential source data types: point data, gridded data, contour lines. 18
19 Data Conversion Processing Steps Interpolation of sparse point data (e.g. generation of DEM) if required. Point data with sufficient coverage can be used to generate contours (3D or 2D with depth attribute) 19
20 Data Conversion Processing Steps Contours in other formats are converted to S-57 and encoded accordingly If required coordinates are transformed to lat, lon WGS-84. 20
21 Data Conversion Conversion Result S-57 DEPCNT 21
22 benc - Finishing up 22
23 benc - finishing up Creating area objects Definition of cell boundary (encoded as M_COVR) Use M_COVR object to clip depth contours Automatic creation of depth areas (including attribution). Meta information (survey date, survey authority, data quality, etc.) 23
24 Creating area objects benc - finishing up Definition of Cell Boundary. Automatic Creation of DEPARE Objects. 24
25 benc Product Specification 25
26 benc Product Specification benc characteristics Dataset Identification Field PRSP = 200. benc have a usage range e.g. from 6 to 9. bencs do not have to be rectangular. No sequential updates => New Editions 26
27 benc characteristics benc Product Specification Allowed object classes: DEPCNT, DEPARE, DRGARE, SOUNDG, UNSARE, M_COVR, M_QUAL, M_SREL M_SDAT, M_CSCL, M_NPUB File Naming: CCBPXXXX XXXX = individual cell code P = lower value of the range of the navigational purpose B = Product Id (bathymetric ENC) CC = Producer Code 27
28 benc Processing Steps (some details) 28
29 benc Processing Steps 3 Examples: 1. Contouring with Contour Generator. 2. Data Conversion with FME and FME Writer Plugin. 3. Automatic creation of depth areas (including attribution). 29
30 benc Processing Steps Example 1 Contour Generator Plugin 1(2) Read Point Data. Set Product Properties 30
31 benc Processing Steps Example 1 Contour Generator Plugin 1(2) Read Point Data. Set Product Properties Set Contouring Parameters - Scale - Depth Multiplication Factor - Start value and - Contouring Interval 31
32 benc Processing Steps Example 1 Contour Generator Plugin 1(2) Read Point Data. Set Product Properties Set Contouring Parameters - Scale - Depth Multiplication Factor - Start value and - Contouring Interval Start Contouring and view result. 32
33 Processing in Detail Example 1 Contour Generator Plugin 2 (2) A set of S-57 DEPCNT objects have been created. Each DEPCNT object is encoded with the attribute VALDCO. The next steps are the definition of an outer boundary and the generation of DEPARE objects. 33
34 benc Processing Steps Example 2 Conversion with FME 1(2) View source data in FME Viewer. Identification of relevant layers and/or attributes. Determine if contours are 3D or 2D. Verify if coordinate system information is available. 34
35 benc Processing Steps Example 2 Conversion with FME 2(3) Launch FME Workbench Specify Source and Destination datasets Set benc Product properties. Define Source Data Coordinate System. Then create FME workbench for conversion flow. 35
36 benc Processing Steps Example 2 Conversion with FME 3(3) Source Dataset Destination Dataset Feature Types Source Data Feature Types Destination Data Source and Data and contained feature types Destination Data and S-57 objects Coordinate Transformation Parameters Feature Mapping and Data Manipulation Transformers for Data Manipulation and Feature Mapping Coordinate Transformation Parameters. 36
37 benc Processing Steps Example 3 Make Skin of The Earth 1 (2) An outer boundary must have been defined and encoded as M_COVR with CATCOV=1. Each DEPCNT object must have an attribute VALDCO. 37
38 benc Processing Steps Example 3 Make Skin of The Earth 1 (2) An outer boundary must have been defined and encoded as M_COVR with CATCOV=1. Each DEPCNT object must have an attribute VALDCO. When the tool is started DEPARE objects will be created automatically. 38
39 benc Processing Steps Example 3 Make Skin of The Earth 2 (2) All DEPARE objects are encode with DRVAL1 and DRVAL2. Meta information should be encoded: - Survey date - Survey authority - Data Quality The benc is ready. 39
40 Maintenance of bencs 40
41 Maintenance of bencs Subdevide big area into smaller areas 00001 00002 00003 00004 00005 00006 00007 00008 00009 00010 00011 Each of the tiles has dedicated Id. 00012 00013 00014 00015 41
42 benc dataset naming Maintenance of bencs 7CB60008 Tile id is part of benc dataset name. 7CB60009 Once the Dataset names have been defined they are fixed. 7CB60010 7CB60011 42
43 Updating of bencs Maintenance of bencs Edition 1 7CB60008 7CB60009 Edition 1 Edition 1 7CB60010 Edition 1 7CB60011 43
44 Updating of bencs Maintenance of bencs Edition 1 7CB60008 Sequential updates are not produced. 7CB60009 Edition 2 A new Edition is created when the data is updated. Edition 1 7CB60010 Edition 1 7CB60011 44
45 Thank you very much for your attention! 45
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