I have been exploring ways to present dynamic data to users in my organization. Our GIS group hosts our data on a spatial database engine and hosts some of the feature layers and datasets as feature services for web apps. I really like using the web apps with the dashboard template to display a map with graphs and data summaries from the widgets. However, my group wants to move into using the operations dashboards more—because they seem to be more customizable on the fly while being hosted through ArcGIS Online (instead of our server hosting a modified web application that has been customized though adjusting the HTML and scripting). So with that I have run into an interesting issue.
In the web application—if I have a feature service in my web map I can run statistics on the feature with the Infographic widget (as long as the feature service is a single layer). I am specifically looking at getting statistics on the SHAPE.LEN field of a line feature using the number template. The Infographic widget is capable of returning a sum of this field so I can get the total length of all the features. This is great and all but: I'm forced to use Filter by extent—as the check box is checked and grayed out. So this limits the sum to the current visible extent of the map (it updates as one zooms in or out) and I would like the entire total displayed.
Trying this same approach in an operations dashboard leads to an error. I bring in the same web map with the same feature service and when I try to do a sum on the SHAPE.LEN field with the 99! Indicator; there is a yellow caution triangle in the corner of the preview with a pop-up that states "Cannot Access Data". The curious things are:
- that if the feature service is being hosted on the ESRI server than I do not get the "Cannot Access Data" error and it very quickly returns the length sum.
- if I try to do a sum statistic on any other integer field in the same feature service the 99! Indicator returns the correct values.
So I am stuck wondering why can the Infographic widget from the web application read/access the shape.length field and the operations dashboard cannot read/access just this one field?
The whole point of trying to do this is to keep the data dynamic and "live" and to avoid having to do database triggers, field calculations and etc. If anyone here has any idea why this is happening or suggestions I would appreciate any ideas or information! Maybe I am missing something very simple here?