1

I have a table of points that looks something like this:

year,   latitude, longitude
2018,   42.02,    -87.68
2018,   41.91,    -87.78
2018,   41.64,    -87.68
2017,   41.63,    -87.56
2017,   41.89,    -87.67
2017,   41.67,    -87.80

Which I used Import XY to import from CSV as a set of points.

Now I want to perform some operation on it, but looping over the year attribute.

So far I got something like this:

import arcpy
imported_points = "imported_points.shp"

for yr in (2017, 2018):
  new_file = "poly_" + yr + ".shp"
  arcpy.SelectLayerByAttribute_management(imported_points , 
                                          "NEW_SELECTION",
                                          "[year] = " + yr)
  # Some operation, using this as an example          
  arcpy.DirectionalDistribution_stats(imported_points , new_file, "2_STANDARD_DEVIATIONS", "#", "#")

However, when I try this I get the following error:

ExecuteError: Failed to execute. Parameters are not valid.
The value cannot be a feature class
ERROR 000840: The value is not a Raster Layer.
ERROR 000840: The value is not a Mosaic Layer.
Failed to execute (SelectLayerByAttribute).

What does this mean? What is the best way to do some operation like this?

marked as duplicate by PolyGeo arcpy Jun 22 at 22:28

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

-2

In ArcGIS you can't use ".shp" file directly for SelectLayerByAttribute_management analysis. First you must make it layer. Try to run your code after modifying like below.

import arcpy

path = "imported_points.shp"
mxd = arcpy.mapping.MapDocument("CURRENT")
df = mxd.activeDataFrame
layer = arcpy.mapping.Layer(path)
arcpy.mapping.AddLayer(df, layer)
arcpy.RefreshActiveView()
arcpy.RefreshTOC()
years = (2017,2018)
arcpy.SelectLayerByAttribute_management(layer.name,"NEW_SELECTION",""" \"year\" IN {} """.format(str(years)))
  • 3
    Why invoke the arcpy mapping module? – Aaron Jun 22 at 20:54
  • It's not necessary when you run the code in ArcMap Python Console. – moortea Jun 24 at 9:01

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