Disappearing feature class?

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5
04-04-2012 08:38 AM
JoshuaChan
New Contributor III
I have a feature class sitting in a personal database (.mdb). The feature class displays fine at scales >= 1:500,000. But once zoomed in closer than that it disappears.
The layer properties show that the "Scale Range" has been set to "Show Layer at all scales"

what else can be causing this disappearing act?
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5 Replies
ChristopherThompson
Regular Contributor
is it all features in the FC that vanish? or just one?   I've encountered this problem in a couple of situations.

The first is for very small features that are being displayed at scales of 1:50 or greater, and i think an ESRI support technician indicated this was a bug though it sounds as if this isn't your problem exactly.

Another issue i've encountered that seems to cause polygon features to vanish has to do with the order/direction of vertices in the polygon.  I think that generally ArcGIS likes polygons to be created in a clockwise fashion so that the index value of vertices increase from 1 to n as you proceed clockwise around the perimeter of a polygon.  If you throw in a polygon that has its vertices ordered in the opposite direction this can cause some issues.  Problems I've encountered that seem symptomatic of this issue include:


  • Polygons vanishing when zooming or panning

  • Polygon fills being applied to the region 'outside' the polygon

  • Negative values being returned when calculating feature areas


Mainly I find this is an issue with polygons that have been manually digitized or when polygons have been created with a GPS unit and the field people have traversed the boundary in an counter-clockwise fashion.  I know it seems weird, but every time I have encountered this issue and inspected the problematic polygons they have been created in reverse order, and recreating them so that they are 'clockwise' polys always fixes the problem.

One way to check this is to start an edit session on your polygons, select and double click a polygon to activate the 'edit vertices' tool, hover your cursor over a vertex as if you were going to move it, then right click and select 'sketch properties' - this will pop up a box that lists the vertices as an ordered list.  If you select them one after the other in order, you'll be able to see if the vertices are ordered in clockwise or counter clockwise fashion.  There I'm not sure if the geometry repair tools fix this problem or not, but I can see where this is a pain if you have many polygons to edit.

I'm not sure if this is a bug or a 'feature' and the product is working as intended by ESRI developers.
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JoshuaChan
New Contributor III
my dataset is a line feature class.

only a small subset of the lines perform this disappearing act. And looking back at some notes, it looks like these lines were added in by some anonymous coworker several years ago.

when I export this feature class into a FGDB (original is in a MDB) it appears at all scales. I wonder if this means my MDB corrupt? ?




is it all features in the FC that vanish? or just one?   I've encountered this problem in a couple of situations.

The first is for very small features that are being displayed at scales of 1:50 or greater, and i think an ESRI support technician indicated this was a bug though it sounds as if this isn't your problem exactly.

Another issue i've encountered that seems to cause polygon features to vanish has to do with the order/direction of vertices in the polygon.  I think that generally ArcGIS likes polygons to be created in a clockwise fashion so that the index value of vertices increase from 1 to n as you proceed clockwise around the perimeter of a polygon.  If you throw in a polygon that has its vertices ordered in the opposite direction this can cause some issues.  Problems I've encountered that seem symptomatic of this issue include:


  • Polygons vanishing when zooming or panning

  • Polygon fills being applied to the region 'outside' the polygon

  • Negative values being returned when calculating feature areas


Mainly I find this is an issue with polygons that have been manually digitized or when polygons have been created with a GPS unit and the field people have traversed the boundary in an counter-clockwise fashion.  I know it seems weird, but every time I have encountered this issue and inspected the problematic polygons they have been created in reverse order, and recreating them so that they are 'clockwise' polys always fixes the problem.

One way to check this is to start an edit session on your polygons, select and double click a polygon to activate the 'edit vertices' tool, hover your cursor over a vertex as if you were going to move it, then right click and select 'sketch properties' - this will pop up a box that lists the vertices as an ordered list.  If you select them one after the other in order, you'll be able to see if the vertices are ordered in clockwise or counter clockwise fashion.  There I'm not sure if the geometry repair tools fix this problem or not, but I can see where this is a pain if you have many polygons to edit.

I'm not sure if this is a bug or a 'feature' and the product is working as intended by ESRI developers.
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ChristopherThompson
Regular Contributor
The .mdb format may well have been the culprit then.  How big is your dataset? Access based GDBs can only store up to about 2gb of data if I recall, and in reality seem to get a little unstable once you hit the 1gb mark, though I can't really offer hard proof of that.
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CoryMacNeil1
Occasional Contributor II
Hi,
Have you tried deleting and then recalculating your Spatial Index (done in the Catalog Window or ArcCatalog)?  I have had something similar many times before, but once I recalculated the Spatial Index it worked fine.

I hope this helps.
Cory
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BettyConces
New Contributor III
This worked for me on an arc feature in a file geodatabase. I wanted to let folks know it could be a good solution for them.
Thanks Cory!
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