topic Re: querying based on map extent in ArcGIS API for Flex Questions

querying based on map extent

ArshadAhmed — Fri, 25 Mar 2011 00:56:51 GMT

Hi,

I'm using a QueryTask that takes a Query and it is querying by the geometry. Basically, I have an event listener that listens for extent change of the US topo map and then takes the map extent and gives it as an input to the Query. But I would like to make sure that the map is zoomed atleast to the state level before I execute the query. How can I find out if the map extent is atleast at the state level or lower and then execute the query? I hope this question is clear.

Thank you,
Arshad.

Re: querying based on map extent

FaizanTayyab — Fri, 25 Mar 2011 08:52:06 GMT

If you know the extent of the state layer, then on each extent change on you can check whether that extent has been reached. If so perform the query.

Re: querying based on map extent

ArshadAhmed — Fri, 25 Mar 2011 12:10:49 GMT

I would like to limit the geometry to the size of a state, so that when a user is panning the map on the state border, it would still return the results. The requirement is the limit the geometry of the query to a size, say the size of the state of virginia. Thank you for your time.

Re: querying based on map extent

FaizanTayyab — Fri, 25 Mar 2011 14:41:27 GMT

Have you looked at:

http://resources.esri.com/help/9.3/arcgisserver/apis/flex/apiref/com/esri/ags/tasks/Query.html

especially at the constants. that might be what you are looking for

SPATIAL_REL_CONTAINS constant

public static const SPATIAL_REL_CONTAINS:String = "esriSpatialRelContains"
Part or all of a feature from feature class 1 is contained within a feature from feature class 2.

SPATIAL_REL_CROSSES constant

public static const SPATIAL_REL_CROSSES:String = "esriSpatialRelCrosses"
The feature from feature class 1 crosses a feature from feature class 2.

SPATIAL_REL_ENVELOPEINTERSECTS constant

public static const SPATIAL_REL_ENVELOPEINTERSECTS:String = "esriSpatialRelEnvelopeIntersects"
The envelope of feature class 1 intersects with the envelope of feature class 2.

SPATIAL_REL_INDEXINTERSECTS constant

public static const SPATIAL_REL_INDEXINTERSECTS:String = "esriSpatialRelIndexIntersects"
The envelope of the query feature class intersects the index entry for the target feature class.

SPATIAL_REL_INTERSECTS constant

public static const SPATIAL_REL_INTERSECTS:String = "esriSpatialRelIntersects"
Part of a feature from feature class 1 is contained in a feature from feature class 2.

SPATIAL_REL_OVERLAPS constant

public static const SPATIAL_REL_OVERLAPS:String = "esriSpatialRelOverlaps"
Features from feature class 1 overlap features in feature class 2.

SPATIAL_REL_TOUCHES constant

public static const SPATIAL_REL_TOUCHES:String = "esriSpatialRelTouches"
The feature from feature class 1 touches the border of a feature from feature class 2.

SPATIAL_REL_WITHIN constant

public static const SPATIAL_REL_WITHIN:String = "esriSpatialRelWithin"
The feature from feature class 1 is completely enclosed by the feature from feature class 2.