Esri Mapping Center - Ask a Cartographer

Symbol levels in free representations

January 27 2010 | 6 comments
Categories: Cartographic Representations, Symbology

I have a feature with a free representation (a highway) which I'm using to draw an overpass symbol where it crosses another feature (major road) which is displayed using a representation.

The overpass symbol is drawn in the Free Representation Editor, where it appears on top of the major road. However, in the regular view it appears below all other representation symbol levels and I can't find a way to change this. What do I need to do to accomplish this?

Mapping Center Answer:

We are aware of this problem. There's no way currently to define what the symbol level is for components in a free representation. We made a change to have any new component in a free representation created with the highest level available so that it draws on top, but there are still some issues. It's probably not going to be addressed immediately but we are aware of this.

In the meantime, it sounds like the Create Overpass GP tool would be a better solution.

Create overpass posted by Hans van der Maarel on Jan 27 2010 11:01AM

Doesn't the 'Create Overpass' tool require the 'over' and 'under' features to be in seperate layers? That's not an option given the dataset we have.

Def query posted by Aileen Buckley on Jan 27 2010 11:14AM

Can you use two copies of the same feature class with definition queries to include or exclude features in the two copies? IF so, then you still only have one feature class in teh database, but you have the two required input layers for the Create Overpass tool.

yeah, that might work posted by Hans van der Maarel on Jan 27 2010 11:36AM

Hi Aileen,

Yeah, that might work. We'll need to make some changes to the data model to deal with that but there's no complex intersections in the area of interest, just simple over/underpasses, so it'll be relatively easy.

However, since that would involve adding a second copy of our roads dataset I'm concerned about processing/rendering times. Would it be possible to create a view in the geodatabase and use that?

processing time posted by Aileen Buckley on Jan 27 2010 12:59PM

The processing time would certainly speed up if you used a copy of the data wihtout a dynamic query. In other words, "extract" the features into two separate feature classes. But then you have a whole different set of issues to deal with.

Not sure what you mean by a "view" in the database. If you clarify, I can try to answer that.

View posted by Hans van der Maarel on Jan 28 2010 4:42AM

A view is an SQL query in a database that can be used as if it were a table. I know this would work in Oracle or PostGIS, haven't been able to try it with a geodatabase (.gdb) yet.

Def query - again posted by Aileen Buckley on Jan 28 2010 2:01PM

If you use a definition query on a layer, then you are essentially extracting a view of the data but not changing the data themselves. The def query can be used to determine which features to SHOW or which NOT to show -- as you please. The thing is that it is a dynamic query so it talked a little more processing time than if you used a layer that ONLY had the features you wanted to show. In my experience, the processing time difference is negligible.

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