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MapFrame and using exportToPNG(), is this a bug?

Hornbydd

All,

I came across this Q&A on GIS Stack exchange, the poster wanted to export the MapFrame in a layout to a PNG which was zoomed to a feature defined by a definition query, but it creates a much large extent of output when exported .

Someone answered, but their code does not really work. I adapted their code to adjust the extent of the MapView and camera objects, but like the original poster I too end up exporting a much larger PNG.

So my question is, is this by design or a bug in ArcPro 2.9.2 arcpy? If the MapFrame is showing a zoomed in section of the data I would have expected the export process to export only that?

The code is this:

import arcpy
arcpy.env.overwriteOutput = True

myPrj = arcpy.mp.ArcGISProject('current')
myLayout = myPrj.listLayouts("FirstPrintLayout")[0]
mapframe = myLayout.listElements("MAPFRAME_ELEMENT", "Map Frame 1")[0]

for lyr in mapframe.map.listLayers("River Centreline 2006"):
    if lyr.supports("DEFINITIONQUERY"):
        print(lyr.name, ' has defQuery ', lyr.definitionQuery)
        print ('Excellent! So now lets get the extents')
        mapExtent = mapframe.getLayerExtent(lyr)

        print (f'5 - mapFrame  XMin extents: {mapExtent.XMin}')
        print (f'Ymin {mapExtent.YMin}')
        print (f'XMax {mapExtent.XMax}')
        print (f'YMax {mapExtent.YMax}')
        
        mapframe.camera.setExtent(mapExtent)
        
        theMapView = myPrj.activeView # This line expects the Map to be Active Not Layout.
        theMapView.panToExtent(mapExtent)
               
        # Export Map Frame
        mapframe.exportToPNG(out_png='c:\Temp\outimg.png', resolution=60)
        print('Export completed!')

Note: my sample data is in British National Grid

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Accepted answers

jbarrette

Duncan, we figured it out. MapFrames were hard-coded to pageunits=inches and you were using mm. The extent was so far off because of the conversion from units to pixel space, etc. We should have this fixed in Pro 3.0. So the work around continues to be what I suggested above or changing your page units to inches (which I know is not something you may want to do). Thank you so much for reporting this. I'm surprised it took so long to be discovered.

Jeff - Layout and arcpy.mp teams.

All comments

Hornbydd

@JeffBarrette ,

Here is a map package with a totally different dataset. I have applied a def query on one polygon (PID = 26), then run the code below:

import arcpy
arcpy.env.overwriteOutput = True

myPrj = arcpy.mp.ArcGISProject('current')
myLayout = myPrj.listLayouts("FirstPrintLayout")[0]
mapframe = myLayout.listElements("MAPFRAME_ELEMENT", "Map Frame 1")[0]

for lyr in mapframe.map.listLayers("fcTestData"):
    if lyr.supports("DEFINITIONQUERY"):
        print(lyr.name, ' has defQuery ', lyr.definitionQuery)
        print ('Excellent! So now lets get the extents')
        
        # Select zoom to then clear selection on the polygon defined in definition query
        sql = "PID = 26"
        arcpy.SelectLayerByAttribute_management(lyr,'NEW_SELECTION',sql)        
        mapExtent = mapframe.getLayerExtent(lyr,True)
        arcpy.SelectLayerByAttribute_management(lyr, "CLEAR_SELECTION")

        print (f'5 - mapFrame  XMin extents: {mapExtent.XMin}')
        print (f'Ymin {mapExtent.YMin}')
        print (f'XMax {mapExtent.XMax}')
        print (f'YMax {mapExtent.YMax}')
        
        mapframe.camera.setExtent(mapExtent)
                       
        # Export Map Frame
        mapframe.exportToPNG(out_png='c:\Temp\outimg.png', resolution=60)
        print('Export completed!')

I have modified the code slightly to zoom into the selected feature

sql = "PID = 26"
arcpy.SelectLayerByAttribute_management(lyr,'NEW_SELECTION',sql)
mapExtent = mapframe.getLayerExtent(lyr,True)
arcpy.SelectLayerByAttribute_management(lyr, "CLEAR_SELECTION")

So I open the project, open Python console and paste the above code in and run it. The output is an png zoomed to the extent of the layer, not the zoomed in selected feature, BUT the map fame has zoomed in, you can see this in the layout. It seems to me that export process is not honouring the extent the map frame is displaying but that of the layer?

testdata.ppkx

jbarrette

I was running your code in the Python Window. You are more than welcome to send me a small PPKX so I can ensure we don't have an extent bug.

jbarrette@esri.com - Layout and arcpy.mp teams

Hornbydd

Jeff,

Thanks for looking into this issue. Lines 21 & 22 were my attempt to see if the MapView was in some way overriding the MapFrame extent which gets sets by the definition query extent.

I wonder if the format of the data is in someway influencing the export process? E.g. is it a shapefile or geodatabase featureclass or do polygons work but not points?

How were you running the script, in the python console (as I had) or via notebook?

I will have another go and try it with some other dataset and report back.

jbarrette

Hello Duncan, I can NOT reproduce the issue. The script successfully sets the MF extent by zooming to the features that match the Def Query. For me the exported PNG extent matches the MapFrame extent I see on the layout.

Lines 21 and 22 do not make sense to me in the context of exporting a MapFrame. You must be running the script with the LayoutView active instead of the map view. If I activate the MapView and run your script, it all works as expected: The MapView extent is only panned, while the MapFrame extent is zoomed to the QueryDef features.

I tried all this on 2.9. If you could provide more detail, I'd be happy to look futher.

Jeff - Layout and arcpy.mp teams

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