finding an area not within a certain distance from a hydrant

[MikeHenson]

I use arcgis a bit, but typically just for some data collection/conversion to cad. I have been given a task.  This task in on a water system map with fire hydrants on it.  My engineer is wanting me to find all areas not within 400 feet of an existing hydrant. This would show me areas not covered by fire protection.  I am just needing the steps on how to create this query. Any help would be greatly appreciated.

[JakeSimms1]

Mike, good question.

So this would depend on how you are consuming the points feature class. Are you doing this in ArcMap/ArcCatalog/ArcGIS Pro, in a service via rest, or though a RDBMS (SQL Server, Oracle, etc)?

- Jake

[MikeHenson]

Thanks for the reply jake. I'm just using arcgis desktop, so will be querying shape files from there.

[JakeSimms1]

So the best way to do this is:

1. Create a buffer around the points. Within the buffer use Dissolve Type : All to create a single feature. 

2. Use the Minimum Bounding Geometry to create a boundary shapefile extent of your points. Make sure Geometry Type is ENVELOPE.

3. Then use Erase. Make sure to use in feature would be the buffer feature and the erase feature is the boundary shapefile. This output would be the areas you want. BE AWARE - some of the features may be outside the extent you want. You can use the Multipart to Single part to create individual features in the feature class. then delete the parts you do not wish to include.

Hope this helps

- Jake