Using ArcPy to zoom to selected feature?

Question

Is there a way to zoom to the extent of a selected feature using the ArcPy module in ArcGIS Desktop 10.

Answer 1

I've got a piece of code that works. I found it here on the ESRI website. Add it as a script to a model, then connect the output of a select by attribute tool to it. It does exactly what I want.

import arcpy
mxd = arcpy.mapping.MapDocument('CURRENT')
df = arcpy.mapping.ListDataFrames(mxd, "Layers") [0]
df.zoomToSelectedFeatures()
arcpy.RefreshActiveView()

Answer 2

As you've already surmised,

df.zoomToSelectedFeatures()

will change the extents of the data frame to all selected features in the map frame. If you're interested in just zooming to a selection set for a specific layer then use lyr.getSelectedExtent(). I also adjust the map scale factor so my code either looks like this:

df.extent = lyr.getSelectedExtent()
df.scale *= 1.5
arcpy.RefreshActiveView()

or this:

df.extent = lyr.getSelectedExtent()
df.scale = 12000 # 1:1,000
arcpy.RefreshActiveView()

Answer 3

I'd say yes. The layer class has a getSelectedExtent method, and the Dataframe has an extent property. Haven't tried it though.

Answer 4

So, to add to this, I've been needing to keep track of the broadest extent across multiple layers with no features selected. The following code will track the furthest extent in each direction. extent_object stays constant across all calls to the function and should be initialized to one of the layers you are including. The argument "layer" to track_extent is an arcpy.Mapping.Layer object. When you are ready to save your map, just set your dataframe's extent via something like data_frame.extent = extent_object

extent_object = initial_layer.getExtent()

def track_extent(extent_object,layer):

    l_properties = layer.getExtent()

    # each of these essentially says that if this layer is further out to one direction than the current setting, change the setting
    if l_properties.XMin < extent_object.XMin:
        extent_object.XMin = l_properties.XMin
    if l_properties.YMin < extent_object.YMin:
        extent_object.YMin = l_properties.YMin
    if l_properties.XMax > extent_object.XMax:
        extent_object.XMax = l_properties.XMax
    if l_properties.YMax > extent_object.YMax:
        extent_object.YMax = l_properties.YMax