Open Data Download to shapefile has topology degradation

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11-05-2015 10:52 AM
SteveGay3
New Contributor II

We have uploaded a street centerline data set has a hosted services.  It is shared to our open data portal.  When it is downloaded using the tool in the portal the shapefile geometry is altered to the point it does not have connected end points.  We verified that the source before upload is accurate.  Also the the hosted feature service is correct when viewed in ArcMap.

See link below to our portal page. 

Dataset | City of Elk Grove - Open GIS Data

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SteveGay3
New Contributor II

I initiated a help ticket with Esri and they helped me verify that the issue was not related to downloading the data from the site.  Rather a rendering issue with ArcMap.  We also noticed that if a feature class is uploaded to ArcGIS.com with a feature containing a sliver polygon it renders oddly.  In somecases it renders as expected (Small sliver) in other cases it renders as the full extent of the projection being displayed.  We resolved the sliver and the behavior disappeared.

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DanPatterson_Retired
MVP Esteemed Contributor

Is your source data of a type that supports precision types?

Migrating to high precision—ArcGIS Help | ArcGIS for Desktop

The shapefile might be reflecting that difference in the precision which may be acceptable of the underlying tolerance.  A shapefile doesn't accept tolerance differences, nor does it support topology so nothing will be snapped together if it wasn't connected initially.  This would probably be the case if there were a few "issues" but if it is all features, then you have an underlying bigger problem.

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SteveGay3
New Contributor II

Thanks Dan,

The source data we uploaded has is in SDE and has high precision.  we compared the data from 4 perspectives:

1 source in SDE

2 a shapefile exported from SDE

3 the online feature class

4 the shapefile exported from ArcGIS online opendata

the first 3 maintain the expected geometry and precision.  The 4th causes the endpoints to not be connected. 

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DanielFenton1
Regular Contributor

Hi Steve,

Are there any curves in your data?

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SteveGay3
New Contributor II

no curves

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SteveGay3
New Contributor II

We just discovered a similar issue with a polygon layer.  the geometry is significantly degraded.  More so than bad topology.  I just created a support case.

Additonal feedback is welcome.

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SteveGay3
New Contributor II

I initiated a help ticket with Esri and they helped me verify that the issue was not related to downloading the data from the site.  Rather a rendering issue with ArcMap.  We also noticed that if a feature class is uploaded to ArcGIS.com with a feature containing a sliver polygon it renders oddly.  In somecases it renders as expected (Small sliver) in other cases it renders as the full extent of the projection being displayed.  We resolved the sliver and the behavior disappeared.