Arcgis Online Inaccuracies

[ChrisBowles]

Hello,

I've jsut created a map for our Historic Environment Record.  The trouble is all points and polygons seem to out by about 80-90 metres from the features they relate to in the basemaps.  The points shapefile has a GB Ordnance Survey coordinate system, while the shapefiles are in WGS 84.  Both are having the same problem.  Are the basemaps off or am I?  Any help on how to fix this would be very helpful as I would like to go public with the map, but won't until accurate.

Thanks,
Chris

[chrischappell]

Chris Chappell,

Can we get the source data for this layer? It appears that the 28th feature is missing geometry.

Thanks,

Mike

Oh man. If that's it I'm going to bang my head against the wall... 🙂

Well in reviewing the source data in ArcMap (the same as what's attached), there are a 6 features out of 419 that do not have a lat / long. but I think I assumed Lat / Long were just table attributes and not necessarily used to map the data in ArcMap. (if that's what you mean by missing geometry). But I might be missing the point.

See attached.

[chrischappell]

Chris Chappell,

Can we get the source data for this layer? It appears that the 28th feature is missing geometry.

Thanks,

Mike

Mike: It appears the missing geometry was my issue. I deleted the rows with no Lat / Long and now it works perfectly. I assumed that since it was a shapefile, the Lat / Long were just attributes. But the original source was an XY event table. (or Add XY Data). And since those few rows did not have a Lat / Long they did not get mapped but remained in the feature attribute table. I can now understand how ArcGIS Online might shuffle rows or whatever it was doing if the geometry for a few features were missing.

http://tinyurl.com/74vqmc6


Thanks,

Chris

[MikeMinami]

Chris,

Glad you got it working. We've made some fixes in ArcGIS Online to better handle features without geometry, so this won't be an issue moving forward.

Thanks,

Mike