Instructions provided help users to understand the Metadata Explorer Web application and provides useful hints to troubleshoot common issues that may arise while working on the application. This article also provides a deeper understanding of the workflow.Metadata Explorer is a Java-based Web application and for it to function correctly, it directly or indirectly makes use of the following:ArcIMS - metadata service
ArcSDE - metadata storage
ArcIMS - image service for the search map
When troubleshooting, it is important to isolate the problem area and work on it accordingly. Below are steps that can help to either identify or resolve common issues.
- If a compilation or runtime error occurs when opening the Metadata Explorer application in a Web browser, the servlet engine log files have to be searched for more information. The source code for the application is available.
The example below displays the Metadata Explorer deployed on Tomcat:
|_ *.jsp, *.htm ==> Source code
|_ *.css, *.xsl ==> Styling elements
|_ *.gif, *.jpg ==> all the images and icons used in the application
|_ web.xml ==> deplyment descriptor
|_ lib ==> contains the ArcIMS Java connector jar files
|_ classes ==> contains the properties files used to configure the application
The above file structure adheres to Java 2 Platform, Enterprise Edition (J2EE) standard and can be modifed easily using any standard Java Development IDE, such as Eclipse, Netbeans or Sun Java Creator.
Understanding 'aimsmeta.properties' file :
Modify this file to set up the Metadata Explorer Web application. The following section addresses some common issues:
- 'meta_host_name' specifies the machine name on which the ArcIMS Metadata Server is running.
- 'meta_service_name' specifies the metadata service name. The service name is case sensitive. Specify the name exactly as it appears in the ArcIMS Administrator.
- 'search_service_name' specifies the search map service started. The service name is case sensitive. Specify the name exactly as it appears in the ArcIMS Administrator.
- 'search_host_name' specifies the machine name on which ArcIMS is running on. This could be the same or a different ArcIMS Instance from the metadata service.
- 'debug' indicates to the Web application that all the requests and responses from the Metadata Explorer should be logged into the servlet engine log file. It is useful to set this to 'true' when debugging or troubleshooting.
- If the Metadata Explorer is visible but the search map is not, the probable causes might be:
A) The service name specified is wrong.
Service names are case sensitive and need to be specified exactly as shown in the ArcIMS Administrator.
B) The map service might not be running. In this case check the ArcIMS Administrator to verify if the service is running. Refresh the service if needed. A good test for this would be to create a HTML viewer using this search map service and check to see if it works as expected.
- If the Web application opens correctly and the search map is shown but no results display when selecting an area on the search map, there might not be any documents published within the area selected or the search map service data and units are not in decimal degrees.
One of the requirements for search map service is that the data and map units are in decimal degrees.
- If there are no results returned when clicking the browse button in the Web application, consider the following:
- Documents are not indexed.
- The URL specified in the metadata service does not have a fully qualified domain name (FQDN) address.
- ArcSDE is not running or there are issues between ArcIMS and ArcSDE communication. In this case the ArcIMS Metadata server log files are a good place to check.
- To do a quick test, open ArcCatalog and search for metadata. If the search fails, the problem is with metadata service. If it returns only a few results, the documents are not indexed.
- If the browse button returns a result but search by theme does not:
- The metadata documents do not have valid theme names as specified in the documentation.
For an out-of-the-box Metadata Explorer, the document themes' keyword should be one of the following: (Ref: page 56 of 176 - Creating and Using Metadata Services.pdf)
- The following are a few good practices:
- It's safe to have validation='true' in the .axl file used to start the metadata service. This checks for the following five elements necessary for correct functioning of Metadata Explorer:
- It's advisable to update the index either manually or use the automatic option in the .axl file. It is important to note that if publishing a large number of documents and not all have been published at the same time, there are chances that the index might be fragmented.
- If needing to modify the content of a metadata document that has already been published, do not edit the published metadata document directly. It is a good practice to modify the original metadata document and republish.