Looping through features

Question

Hello

I'm quiet new in python and i have the following question.

I want to export my map into jpg's with worldfile. Therfore i created a polygon-featureclass with a grid (400 objects). 
As it is a little uninteresting to select and pan to every single polygon and export it, i tried to write a script doing that for me.
The problem is that i do not know how to loop through the features.

This is the code a made.import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
gridLayer = arcpy.mapping.ListLayers(mxd, "Grid", df)[0]
arcpy.SelectLayerByAttribute_management(gridLayer, "NEW_SELECTION", "SORT_ID = 1")
df.extent = gridLayer.getSelectedExtent(False)
df.scale = 100000
arcpy.mapping.ExportToJPEG(mxd, r"C:\Daten\Images\Image1.jpg", df, df_export_width=1600, df_export_height=1200, world_file=TRUE)
del mxd

Thank you in advance,
Jo

MathewCoyle · Answer

You are using df.zoomToSelectedFeatures()

But no where are you making a selection. And if you are starting with a selection in ArcMap it is getting cleared after the first iteration at this line.arcpy.SelectLayerByAttribute_management(fc, "CLEAR_SELECTION")

JohannesRein · Answer

The looping and nameing of the files work, but all images have the same extend.
Why does the extend not update?

It seems that ArcMap does not like the script. It crashed several times.>>> import arcpy
... from arcpy import env
... from arcpy import mapping
... env.workspace = r"C:\Daten\Test"
... mxd = mapping.MapDocument("Current")
... df = mapping.ListDataFrames(mxd, "Layers")[0]
... fc = "Grid_100k"
... count = str(arcpy.GetCount_management(fc))
... x = 1
... while x < int(count) + 1:
...     rows = arcpy.SearchCursor(fc, "MAP = '" + str(x) + "'")
...     print(x)
...     for row in rows:
...         df.zoomToSelectedFeatures()
...         df.scale = 100000
...         arcpy.RefreshActiveView()
...         arcpy.mapping.ExportToJPEG(mxd, r"C:\Daten\Test\100k_" + str(x) + ".jpg", df, df_export_width=5866, df_export_height=3106, world_file=True)
...         print('Bild exportiert')
...         print(x, 'von', count)
...         arcpy.SelectLayerByAttribute_management(fc, "CLEAR_SELECTION")
...     x += 1
... print("Export beendet")

FabianBlau · Answer

arcpy.SelectLayerByAttribute_management("Grid_100k", "NEW_SELECTION", "\"SORT_ID\" = %i" % x)

orarcpy.SelectLayerByAttribute_management("Grid_100k", "NEW_SELECTION", "\"SORT_ID\" = " + str(x))

you also can use a for-loop, for example:for x in range(1, count+1):