Page 2 of 2 Previous Obligation and Recommendation of Metadata Items in Metadata Standards There are total 409 items listed in the metadata dictionaries in ISO19115. The actual number of metadata items may be slightly different from that listed in the dictionaries since the listed items include those being the aggregated classes and role names. Not all those items are required to be filled up in order for a metadata to conform to ISO19115. The standard does specify type of obligation/condition for each metadata item. Only a relatively small number of metadata items are specified as mandatory in ISO19115. Apart from that obligation/condition specification, ISO19115 does also recommending a basic minimum number of metadata elements, which should be maintained for a dataset, typically for catalogue purposes. This is called the 'core' metadata elements. List of mandatory and core metadata items identified by ISO19115 will not be shown here, but reader should be able to access the full ISO19115 document from his or her National standard body. The FGDC's CSDGM metadata standard does also specifying the mandatory metadata items. It also specifies metadata items, which are mandatory if applicable. The full CSDGM standard document is freely available for downloading at FGDC website. Prioritization of ISO19115 Metadata Items From the users' point of view over importance of metadata items and the abilities to fill up those items, the paper presents a metadata item prioritization processes. Firstly, the importance score for each metadata item, given by all fifty interviewees were added up. The importance scores range from 131 to 228. These scores were then classified into three levels as shown in Table 1. For filling up the abilities, the score were assigned basing them on the percentage of interviewees answer 'yes' to the question. The resulted filling-up scores range from 26 to 100. The scores were also classified into three levels as shown in Table 2. Table 3. Few metadata items prioritized as 'Very Important'
By considering the obligation and recommendation of metadata items given by both ISO19115 and CSDGM standards, together with the above importance and filling-up ability level, the metadata items prioritization scheme was developed. Four classes of metadata items are to be determined from the prioritization processes i.e. the most important metadata items (A), the important metadata items (B), the beneficial metadata items (C), and the optional metadata items (D). Figure 1 reveals the prioritization scheme that was used in the study.  Figure 1. Metadata items prioritization scheme After classifying all the ISO19115 metadata items based on the prioritization scheme in Figure 1, the result has been closely inspected. This was to identify and adjust any unexpected priority class assignment which may because of interviewees' misinterpretation of the question asked in the questionnaires or by their misunderstanding of the meaning of particular metadata items themselves. After inspection and adjustment, the metadata items identified by ISO19115 were then prioritized. Only the items classified to be the very important metadata items (A) are shown. In Table 3, certain items are listed with the ISO19115 mandatory items shown in white. From the prioritization results demonstrated above, some interesting observations can be made as:
Toward the Development of Metadata Standard Thailand became P-member of ISO/TC211, in 1997 when the technical committee responsible for the development of International Standard on Geographic Information. The strategy for the development of our National Standards for Geographic Information has therefore been set to adopt or adapt the relevant International Standards published by ISO/TC211. Thailand has already adopted ISO19115 as its present National Standard. Nevertheless, there are still needs for extending that high level International Standard into one that corresponds better to the local situation and requirements of Thai users. In this regard, ISO19115 has a section describing the methodology for extending metadata. This is to ensure that only valid extensions are made to the standard set defined by ISO19115. Possible extensions identified include:
ISO19115 specifies that a new profile can define a more stringent obligation for specific metadata items. The metadata obligations defined in the ISO19115 cannot be relaxed in a profile. For the development of Thailand's national metadata standard, the list of 'very important metadata items' shown in Table 3 should be considered by the authorities involved in defining them a more stringent obligation. Some of them could be defined as 'Mandatory' items while some could be defined as 'Conditional' items. Conclusions The results in the study were analyzed together with the metadata items' obligation specification of ISO19115 and the FGDC's CSDGM metadata standard. In general, Thai users' opinions on metadata requirement conform to both the ISO19115 and CSDGM specifications. However, a number of metadata items related to coordinate reference system, lineage of data, and security constraints appear to be a major concern of most of Thai users. It is also concluded that the prioritized metadata items from the study could and should be defined with a more stringent obligation specification. Also, some additional and modified codelists should be introduced into the Thailand National profile of ISO19115.
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