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Symbology held in a database

February 13 2008 | 2 comments
Categories: Cartographic Representations, Symbology

We still use ArcGIS 9.0 and I've been looking at 9.2 and in particular Representations. We have a series of Customer Renderers that we use for creating Well symbols etc. They use a defined code in the Feature Class to link to our company's specific style file.

In 9.2 I see that we take a step forward and can imbed symbology in a Db albeit a PersonalGdb?
However a colleague has informed me it is already possible to do this in 9.0?

Is this true? ...and if so how would I do this?

Mapping Center Answer:

Any geodatabase (personal, file, or SDE) will store representation symbolgy at version 9.2.

Several people (users and business partners) have written custom renderers in ArcObjects in the past that depended on symbology stored in a blob field. This was based on the idea that the Style file did exactly the same thing; i.e., the symbol objects are just stored in binary blob. Some of these folks may even have been pretty efficient about it, using a related table instead of redundantly storing the same symbol for each feature that used it.

Representations, however, are more than simply storing a symbol in a field. There is an incumbant schema that acts as a framework to manage these symbols. Within that schema is a data structure that allows individual properties of a given feature's symbol to be overridden allowing just that feature to have a custom depiction. The trick is that the only extra data stored is the value for that one setting that is overridden; not a complete custom version of the symbol. Representation symbology can be edited as geometry, so if you wanted to make part of given feature's line symbol wider, you could do that with what is called a free representation.

In the end you will need to evaluate what your custom renderers are doing for you, whether that can be completely replaced by representation symbology or not. If not, your custom renderers will still work, and even if you go to a home brewed method of storing symbols in a database, you'll still need a custom renderer to consume them.

Given the company (I edited this out of your question so I could keep this question public because I think quite a few people are dealing with this issue) you work for, I would suggest getting in touch with your ESRI account representative and see about getting one of our technical folks out there to do a Q&A about what's possible with representation symbology, and specifically discuss whether representations could replace some or all of your custom renderers.

Thanks for the reply posted by Ian Lawrence on Feb 14 2008 12:51AM
thanks for the reply. I'll follow up on that Q and A.
Many thanks.
ANSI standard stormwater symbology posted by David Carlan on Jun 13 2008 5:52AM
I am trying to find ANSI standard stormwater symbology to convert existing points in our GIS. We are currently using point from the standard symbology library that came with our ARC GIS software, but they are not the industry standard symbol. Do you plan on including these symbols in your future symbol libraries? If not do you know of any websites that I might be able to download them? This is my second attempt to find information concerning this. i would appreciate any suggestions you might have.
David Carlan
Bartow County GIS Technician

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