This was a blog post March 17th, but I decided to keep it as its own page for now.
As the County moves toward an integrated GIS environment, a critical piece to the distribution of data is Metadata. Metadata is “data about data,” and explains to users who have never seen the data before how to use it. As I write metadata, I try to write as if I will never see or talk to the person who is using the data, so everything needs to be available to the user.
Metadata is complex and challenging to write, and takes a lot of patience and practice. But basically, here are some tips:
- Use plain English
- Explain the usefulness of the data in the summary, and discuss WHY this data was created. It was created to serve a purpose – explain that.
- Write about the most useful fields or columns in the data, and TRANSLATE: CT00 is not valuable until someone understands that is stands for “2000 Census Tract Number”
- Make sure the year of creation is there – this is very important for usage.
- Also make sure you discuss the accuracy of the data, and the basemap it came from – whether parcel, Thomas Brothers, TIGER, etc.
- And last – provide contact information so that people who have questions about the data can get in touch with you.
As part of the Enterprise GIS Steering Committee, we will be looking in more depth at how to simplify the metadata creation process. Our first starting point is the ESRI metadata explorer, which we publish from our central repository. The website is http://egis3.lacounty.gov/metadataexplorer
Publishing metadata about datasets to this service is straightforward. Here are the requirements:
- GIS Data with required metadata fields:
- Spatial Extent
- Content Type
- Write access to the metadata repository. Right now everyone has access, but we will restrict access in the future.
Step 1: Download Templates
I have created a set of metadata templates that will hopefully make metadata creation a bit easier. These are .xml files that give some text about the basemap information that sites behind a lot of data.
Depending upon your data source, download, change the extension to .xml and import (more in a second).
- Thomas Brothers base – download source_tb.xml.txt
- Assessor base – download source_assessor.xml.txt
- Geocoded data – download source_geocode.xml.txt
- Registrar data (political data) – download source_rrcc.xml.txt
Step 2: Import Templats in ArcCatalog
In ArcCatalog, navigate the dataset you are writing metadata for, and click on the “Metadata” tab – usually above the right-hand pane.
On the top bar, you should see the metadata tools activate – click on the “import metadata” icon. Select “XML” as the format, browse to the locat of the metadata template you downloaded, and click “OK”
Once the metadata has been imported, it is now time to write and edit to match the dataset you are importing, and publish.
Step 3: Complete Metadata and publish
ESRI has produced a useful guide to creating metadata as part of it’s documentation titled: Creating Metadata Services
I have pulled out Chapter 4 – Publishing Metadata in ArcCatalog.pdf as a separate document, since it focuses on the general needs of the user. This gives step-by-step instructions for completing and publishing metadata. I don’t feel it necessary to go further, but here is the connection information to our metadata server for publishing:
ArcIMS server is http://gis3.lacounty.gov, and the metadata service is called LA_County_Metadata
The full metadata document from ESRI is Creating_Metadata_Services.pdf. This document is very large, confusing, and is only useful for metadata administrators.
Good luck – let me know if you have questions.
Update March 26
Since the Built-In Metadata editor is such a pain, I have done some research to find easier Metadata Editors. Here are two that I have found that focus only on the critical metadata:
How to install the tool:
- Create a temporary directory on your hard drive to place the download file.
- Then from this web page download the self extracting zip file into that directory (you may need to right click on the image of the diskette above and select “Save Target As…”.
- In “My Computer” or “Windows Explorer” double click the self extracting file. This will give you three files (setup.exe, ThreeTabEditor.CAB, and SETUP.LST), you may need to refresh your window to see these files.
- Make sure ArcCatalog in NOT open.
- If you have previously installed the tool you should uninstall the tool by going to Control Panel > Add/Remove Programs and finding the Three Tab Editor.
- Install the tool using the setup program provided. Do this by double clicking on “setup.exe”. The Three Tab Editor Setup window will open and request you to press the “OK” button to install the editor. By default the editor will be installed in your “C:Program FilesThreeTabEditor” directory, if you are ok with the directory location then press the large button in the upper left of the screen (it looks like a computer) to proceed with the install. The files will then be copied to the appropriate place on your hard drive. You should get a message that say that the setup was successful, press the “OK” button to close the installation window.
- You may now delete the temporary directory you created in step 1.
- Make sure that your you have set some browser to your default browser. (On most machines this has already been done.) If you don’t have a default browser set the hot links on the form will not work. One way to do this in Windows 2000 is by going to Start > Control Panel > Internet Options > Program (tab), then click on the “Reset Web Settings…” button. This will set Internet Explorer to your default browser.