IHOMX User Manual Ver 1.0

CONTENTSIntroduction......................................................................................................................... 1Applicability ....................................................................................................................... 1How to use IHOMC............................................................................................................ 2Quickstart............................................................................................................................ 2Import Checks..................................................................................................................... 5Support................................................................................................................................ 7

1IntroductionThere has been a significant increase in Electronic Navigational Chart (ENC) Coverageover the past few years; however, it is still difficult to find an authoritative source thatshows all the data that is available.This situation was raised at the 51st session of the IMO Sub-Committee on the Safety ofNavigation (see IMO NAV paper NAV51/6/1) and as a result, the IHO agreed to producean online catalogue showing Global ENC coverage. To do this, the IHB requires up-to-dateinput from all the agencies and producers involved in ENC production and distribution, andin particular the RENCs together with those HO’s that do not distribute their ENCs througha RENC.In order to make the input of data for the IHO on-line catalogue as easy as possible, theElectronic Chart Centre (ECC), in cooperation with the International Hydrographic Bureau,have developed a software application for data harvesting to be used by the RENCs andHO’s. It is known as the IHO Metadata Extraction tool or IHOMX.This document provides a brief overview of IHOMX and describes how to use it. IHOMXcan be downloaded from the IHO web site at http://www.iho.int.ApplicabilityHOs that are members of a RENC. RENCs will use IMOMX to forward all relevantdata to the IHB for the ENCs that are distributed through a RENC.HOs that are NOT members of a RENC. HOs that do not distribute ENCs via a RENCshould use IHOMX to extract ENC coverage and metadata and forward it to theInternational Hydrographic Bureau (ENC_coverage@ihb.mc). Some HOs may also wish topublish and maintain their own metadata records using their own web servers. In such casesthe URL of the web server used for hosting the metadata records (for example:http://TransaviaHO.com/ENC_metadata/) should be included in the “Metadata URLPrefix” field on the “Properties” tab shown in Figure 1 below. This URL property will beconcatenated (joined) to the unique name of each metadata file. (Metadata filenames willbe based on ENC cell names). The resultant string will provide a unique reference to eachmetadata record located on that web resource/server. (for example:http://TransaviaHO.com/ENC_metadata/TS325371.html. Each unique URL references willalso be included in the GML coverage dataset as a property of each coverage feature. Whenthe coverage dataset is used within an application (such as in online catalogues or GIS),users will be able to gain access to metadata records by interrogating the URL property ofthe coverage feature.

2How to Use IHOMXIHOMX extracts both metadata and coverage information from an ENC exchange set. Ituses the ENC “CATALOG.031” file as an index to all ENC cells contained within theexchange set.IHOMX does NOT access, extract or download ENC chart data;IHOMX only looks at and extracts certain ENC metadata.The following metadata is extracted from each ENC exchange set: ENC data limit(M_COVR) [CATCOV = 1] metadata features are extracted and stored in a single GMLfile as individual features. Each coverage feature contains the following attributes; cellname, Compilation Scale (CSCALE) and a URL 1 string pointing to a matching metadatafile located at an online web resource. Whenever a cell limit feature is interrogated (in aninformation system), the matching metadata record will be accessed and displayed.Metadata records extracted from ENC cells are stored in discrete files in both XML 2 andHTML formats. The metadata format used is based on the Draft S-100 Discovery Metadataprofile. After running the application and carrying out the extraction process, both thecomposite GML file and all metadata files are stored in a single compressed (.zip) file.IHOMX maintains the imported ENC metadata in the IHO catalogue database. This makesit fast and easy to compare and update the metadata when new ENC editions and updatesare published. There is no need to reload ENC data into the database, only load additionalinformation.Quickstart1. Starting the application. After downloading the compressed IHOMX file, extract itscontents to a working directory (for example, IHOMX) and start the application bydouble clicking on the ihomx.exe file. The application will start directly and doesnot need the user to go through an installation procedure. It does however requirethe relevant Java Runtime Environment (JRE) to be installed on your computer inorder to operate properly. The relevant java libraries can be downloaded fromhttp://java.sun.com/javase/downloads/index.jsp2. Inserting your organizations metadata. When presented with the data entry formshown in Figure 1 below, insert the relevant metadata for the submittingorganization; which includes Contact Information, Abstract, Purpose, a QualityStatement and Supplemental Information. This information will be added to themetadata archive that is created by IHOMX and will be saved for future use. (Adescription of the underlying S-100 discovery metadata elements used here can befound at Annex A).1 Universal Resource Locator2 eXtensible Markup Language

3Figure 13. Extracting ENC coverage data. The application is then ready to extract theM_COVR feature (coordinates) from each ENC file within a volume, and build asingle composite file containing a coverage feature for each ENC cell. It uses theassociated CATALOGUE file to locate each ENC within the volume.To carry out the extraction process, press the import buttonCATALOG.031 file.and pick theClick “Open” and when the import process has completed you should be presentedwith the message shown in Figure 2 below:

4Figure 2If there are any processing errors or warnings, they will be presented in the formatshown in Figure 3 below. For further information about errors and warnings, checkthe log details.Figure 3

5If errors are reported on an ENC you will not be able to export the metadatainformation for this specific ENC. The error has to be corrected and the importprocess repeated. In addition to the log details you will also find more informationabout import errors and warnings under the heading “Import checks” in thisdocument.4. All cells that are listed under the “Cells” tab (see Figure 4) will be exported to themetadata archive. If you want to add a title to the ENC cell you can type thisinformation in the title box. If you want to remove a cell you can click on the celland use the button to delete it. To export the metadata archive and the coveragedataset, please press the export button . The coverage dataset will be encoded inthe GML 3 format and will be contained within as a single file. (As GML is a textformat, the contents of the file can be viewed using a text editor.Figure 45. The IHOMX application will create a single compressed file containing themetadata files and the coverage datasets. Hydrographic organizations that do notdistribute their data via a RENC organization should send their output files to theInternational Hydrographic Bureau (ENC_coverage@ihb.mc).Import ChecksWhen IHOMX loads an ENC exchange set, it carries out a number of checks on theexchange set. An explanation of these checks is provided below:Reading catalogue file:3 Geography Markup Language

6• Initial parsing of the CATALOG.031 file.Parsing the ENC files in the catalog file• CATALOG.031 and dataset files are parsed according to ISO 8211.• References to TXT and TIF are checked for base cell and re-issue.Looking for reissue.• Checking if it is a re-issue, and then that the extension of the cell name is 000 andthat the DSID UPDN is in sequence with previous loaded data.Checking for previous uploaded data• Make sure that the same data is not loaded twice.Checking if the files exist• Check that all the files in the CATALOG.031 file are readable on disc.Checking filenames• Checking if the filenames are according to S-57 ENC Product Specification 5.6Checking CATD IMPL value• Checking that implementation value (CATD IMPL) is correct in theCATALOG.031 file. Example; ASC, BIN, TXT, TIFChecking crc values• Checking that the CRC values on the dataset files, txt and tif files are identical tothe CRC values listed in the CATALOG.031 fileChecking if DSID DSNM match filename• Checking that the filename (cellname) is identical to the data set name in DSIDDSNMChecking if DSID INTU match cellid• Checking that the intended usage value in DSID INTU is identical to the 3 rdcharacter in the filename (cellname)Checking if the TXT/TIFF files are referred

7• Report TXT/TIFF files in the CATALOG.031 that are not referenced by any datasetfile.Checking for missing TXT/TIFF references in updates• Check that updates references are either included with the update or with an earlierdataset file for the same cell edition.Checking dates• Checking that the dates used are logicalChecking order of updates• Checking that current loaded update is in sequence with previous loaded updateChecking S-57 data structure• Checking that the S-57 data structure is correctChecking geolimit of updates• Checking that the geolimit in the CATALOG.031 file is now wrapped. NLAT >SLAT and ELON > WLON• Checking that the geolimit in the CATALOG.031 file match the dataset coverage.Checking for propagated errors• This message is reported on updates that has an error in previous loaded EN or ERfile.SupportFor questions related to the collection of metadata contact ENC_coverage@ihb.mc.For questions related to the IHOMX program contact support@ecc.as.__________