Wednesday, February 25, 2009 5:00 PM -
mxc@robresint.co.uk
Symbolising data with lost data links

I frequently come across data which has lost data links (a red !). This occurs when the data has been moved or no longer exists, thus breaking the link. On some occasions, even after I tracked down the data and repaired the data source, the symbology still didn’t draw -- it exists, but the wrong field is listed on the Layer Properties Symbology tab. Usually the draw category (Value field) has defaulted to a non-matching field. Simply changing the Value field does not do the trick.

You now begin to envision hours of work to “Re-source” the data. The symbol for each value will have to be saved to a style, and then that symbol will have to be re-matched to the attribute. Of course, you can save some time using the Match to Symbols in a Style option.
However, there is a faster and easier solution! On the Fields tab of the Layer Properties dialog, temporarily turn off all but the required draw fields.

Click on the Symbology tab. The Value Field has now been “forced” to take the field you want to use to symbolize the data. At this point, go back to the Fields tab and turn fields back on. The job is done!

BEFORE: The graphic below shows the map before the data were symbolised corectly.

AFTER: The graphic below shows how the data will look after the edits are made.

Note that if you plan on distributing your maps to others, you might choose to reference data using relative paths. See Referencing data in the map.