[GIS] How to use folders as input/output parameters

arcpy

What I want to do is to go into a folder, find a layer file, pull it into an MXD, then export a jpeg in an output folder. Everything is great except I don't know how to set the input/output folders.

state =  arcpy.GetParameterAsText(0)
In_Folder = arcpy.GetParameterAsText(1)
Out_Folder = arcpy.GetParameterAsText(2)


lyrfile_o = arcpy.mapping.Layer(In_Folder + str(state) + "_O.lyr")
lyrfile_d = arcpy.mapping.Layer(In_Folder + str(state) + "_D.lyr")
lyrfile_lane = arcpy.mapping.Layer(In_Folder + str(state) + "_Lanes_.lyr")
lyrfile_poly = arcpy.mapping.Layer(In_Folder + str(state) + "_Lanes_Polys1.lyr")

and I get an error like:

<type 'exceptions.ValueError'>: Object: CreateObject Layer invalid data source>

It's written in a text editor then brought into a toolbox and parameters set, both types as folders, the first one (state) is a string.

Any ideas?

Best Answer

Suggestions:

Use os.path.join to join folder paths to filenames.
Use string formatting (either the newer .format() method or the older modulo (%) method) instead of the concatentation operator (+)
Do not use output parameters for what are really inputs. In this case the "output" folder is just an input path (string), not an actual piece of data output by your script.
Use an output parameter for data that is created within your script, such as the JPEG file you create. This is optional and is meant to facilitate chaining script tools together in ModelBuilder so in some cases (like this one) it is probably not necessary.
Use an IDE such as PyScripter to debug your Python scripts. PyScripter allows you to specify command line parameters and debug interactively.

Here's an example of combining the first two suggestions (using the older modulo string formatting which is what I'm more familiar with):

lyrfile_o = arcpy.mapping.Layer(os.path.join(In_Folder, "%s_%s" % (state, "O.lyr")))

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[GIS] Adding group layer, renaming it from folder name, then adding layers to it from that folder, using ArcPy/Python

This should work; it worked for me. This will give you a group layer named by the folder and a layer with the name of the shapefile. I built off what artwork21 posted.

import os
import arcpy

WS = r'c:\test_define'
arcpy.env.workspace = "in_memory"

mxd = arcpy.mapping.MapDocument(r"c:\test_define\test_python_add2.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]

for (path, dirs, files) in os.walk(WS):
    for name in files:
        if name.endswith(".shp"):

            groupLayer = arcpy.mapping.Layer(r"c:\test_define\empty_group_layer.lyr")  
            arcpy.mapping.AddLayer(df, groupLayer, "BOTTOM")

            layers = arcpy.mapping.ListLayers(mxd)
            for layer in layers:
                if layer.isGroupLayer and layer.name == "New Group Layer":
                    layer.name = os.path.basename(path)

            newLayer = arcpy.mapping.Layer(os.path.join(path, name))
            arcpy.mapping.AddLayerToGroup(df, layer, newLayer, "BOTTOM")

mxd.save()

You have to make the shapefiles into layers and use AddLayerToGroup. If you want a single group layer for each folder you can recycle this code and modify the os.walk to check for folders with .shp's and go from there. Although, I would recommend trying to contain all these shapefiles into a geodatabase with a proper naming structure and metadata to fit your needs.

To elaborate on the nonrepeating,

import arcpy
import os 

WS = r'c:\test_define'
arcpy.env.workspace = "WS"
mxd = arcpy.mapping.MapDocument(r"c:\test_define\test_python_add2.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
groupLayer = arcpy.mapping.Layer(r"c:\test_define\empty_group_layer.lyr")

for (path, dirs, files) in os.walk(WS):
    for name in files:
        if name.endswith(".shp"):

            layers = arcpy.mapping.ListLayers(mxd)
            name_list = []
            for layer in layers:
                if layer.isGroupLayer:
                    name_list.append(layer.name)

            if os.path.basename(path) not in name_list:
                arcpy.mapping.AddLayer(df, groupLayer, "BOTTOM")
                layers = arcpy.mapping.ListLayers(mxd)
                for layer in layers:
                    if layer.isGroupLayer and layer.name == "New Group Layer":
                        layer.name = os.path.basename(path)
                        newLayer = arcpy.mapping.Layer(os.path.join(path, name))
                        arcpy.mapping.AddLayerToGroup(df, layer, newLayer, "BOTTOM")

            if os.path.basename(path) in name_list:
                layers = arcpy.mapping.ListLayers(mxd)
                for layer in layers:
                    if layer.isGroupLayer and layer.name == os.path.basename(path):
                        newLayer = arcpy.mapping.Layer(os.path.join(path, name))
                        arcpy.mapping.AddLayerToGroup(df, layer, newLayer, "BOTTOM")


mxd.save()

This will check to see if a group layer already exists and will add to it, if so. Else, it will create a new group layer and add the layer.

[GIS] ArcGIS 10.1: “ERROR 000223: Cannot extract event table properties” when iterating through multiple files/folder

First off, I don't think you want to be saving these as layer files (.lyr). A layer file is only a pointer to data. You need to save the data to a feature class or shapefile. The output from the Make XY event layer tool is a "in memory layer" and it is gone once the session is over. That needs to be converted to feature class to save it to your computer.

Try something like this:

arcpy.CopyFeatures_management(out_Layer, "C:/project/year_hour.shp")

The error your getting is probably related to either running out of memory, or because your trying to create an "in-memory" layer that already exists. try deleting the in memory layer after your are done with it:

arcpy.Delete_management(out_Layer)

Best Answer

Related Solutions

[GIS] Adding group layer, renaming it from folder name, then adding layers to it from that folder, using ArcPy/Python

[GIS] ArcGIS 10.1: “ERROR 000223: Cannot extract event table properties” when iterating through multiple files/folder

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