Trying to add a layer (Portal item) to a webmap. The ESRI example for this I'm looking at is very simple: streets_item = gis . content . search ( "LA Streets" , "Map Service" ) [ 0 ] wm = WebMap ( ) # create an empty web map with a default basemap wm . add_layer ( streets_item ) Okay, so I have a web map that's not empty that I created like this: print ( type ( target_item ) ) from arcgis . mapping import WebMap web_map_obj = WebMap ( target_item ) print ( type ( web_map_obj ) ) #>>> #>>> The print() statements are only there to assure myself that I'm actually looking at items on and not itemId's or who knows what. So I have a legit Python web map based on on a web map item in Portal. As a check, I do... web_map_obj . layers # prints out all the layers (map image layers) that nelong to the Portal web map So now, I want to add another layer newLayer = gis . content . search ( query = "new layer" ) ) [ 0 ] # again just checking this is what I expect print ( type ( newLayer ) ) web_map_obj . add_layer ( newLayer ) Well, this bombs... --------------------------------------------------------------------------- TypeError Traceback (most recent call last) in 13 # again just checking this is what I expect 14 print(type(newLayer)) ---> 15 web_map_obj.add_layer(newLayer) C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\arcgis\mapping\_types.py in add_layer(self, layer, options) 323 324 for lyr in layer.layers: # recurse - works for all. --> 325 self.add_layer(lyr, options) 326 return True # end add_layer execution after iterating through each layer. 327 else: C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\arcgis\mapping\_types.py in add_layer(self, layer, options) 510 fields_list = layer.properties.layerDefinition.fields 511 --> 512 for f in fields_list: 513 if isinstance(f, dict) or isinstance(f, PropertyMap): 514 field_dict = {'fieldName': f['name'], TypeError: 'NoneType' object is not iterable What's wrong with what I'm doing? I realize there is also arcgis.gis. Layer . Do I first need to create a Layer from the item and then add that to the web map maybe?

Turns out the syntax of the ESRI example works when adding an item (as layer) to web map using add_layer() works when it was created as empty new web map like this: webmap = Webmap ( ) But not when the web map was created off another item and already has some layers... webmap = Webmap ( item ) This may be explained somewhere in ESRI documentation. Good to know!

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'NoneType" Error when adding layer to WebMap using Python API

Arne_Gelfert

Trying to add a layer (Portal item) to a webmap. The ESRI example for this I'm looking at is very simple:

streets_item <SPAN class="operator token">=</SPAN> gis<SPAN class="punctuation token">.</SPAN>content<SPAN class="punctuation token">.</SPAN>search<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"LA Streets"</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="string token">"Map Service"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>

wm <SPAN class="operator token">=</SPAN> WebMap<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN>  <SPAN class="comment token"># create an empty web map with a default basemap</SPAN>
wm<SPAN class="punctuation token">.</SPAN>add_layer<SPAN class="punctuation token">(</SPAN>streets_item<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

Okay, so I have a web map that's not empty that I created like this:

<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>type<SPAN class="punctuation token">(</SPAN>target_item<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">from</SPAN> arcgis<SPAN class="punctuation token">.</SPAN>mapping <SPAN class="keyword token">import</SPAN> WebMap
web_map_obj <SPAN class="operator token">=</SPAN> WebMap<SPAN class="punctuation token">(</SPAN>target_item<SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>type<SPAN class="punctuation token">(</SPAN>web_map_obj<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍

<SPAN class="comment token">#>>> <class 'arcgis.gis.Item'></SPAN>
<SPAN class="comment token">#>>> <class 'arcgis.mapping._types.WebMap'></SPAN>
‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

The print() statements are only there to assure myself that I'm actually looking at items on and not itemId's or who knows what. So I have a legit Python web map based on on a web map item in Portal. As a check, I do...

web_map_obj<SPAN class="punctuation token">.</SPAN>layers

<SPAN class="comment token"># prints out all the layers (map image layers) that nelong to the Portal web map</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

So now, I want to add another layer

newLayer <SPAN class="operator token">=</SPAN> gis<SPAN class="punctuation token">.</SPAN>content<SPAN class="punctuation token">.</SPAN>search<SPAN class="punctuation token">(</SPAN>query <SPAN class="operator token">=</SPAN> <SPAN class="string token">"new layer"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="comment token"># again just checking this is what I expect</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>type<SPAN class="punctuation token">(</SPAN>newLayer<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>

web_map_obj<SPAN class="punctuation token">.</SPAN>add_layer<SPAN class="punctuation token">(</SPAN>newLayer<SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

Well, this bombs...

<class 'arcgis.gis.Item'>

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-191-62f982ec1c55> in <module>
     13     # again just checking this is what I expect
     14     print(type(newLayer))
---> 15     web_map_obj.add_layer(newLayer)

C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\arcgis\mapping\_types.py in add_layer(self, layer, options)
    323 
    324                 for lyr in layer.layers:  # recurse - works for all.
--> 325                     self.add_layer(lyr, options)
    326                 return True  # end add_layer execution after iterating through each layer.
    327             else:

C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\arcgis\mapping\_types.py in add_layer(self, layer, options)
    510                         fields_list = layer.properties.layerDefinition.fields
    511 
--> 512             for f in fields_list:
    513                 if isinstance(f, dict) or isinstance(f, PropertyMap):
    514                     field_dict = {'fieldName': f['name'],

TypeError: 'NoneType' object is not iterable
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

What's wrong with what I'm doing? I realize there is also arcgis.gis.<A href="https://developers.arcgis.com/python/api-reference/arcgis.gis.toc.html#arcgis.gis.Layer" rel="nofollow noopener noreferrer" target="_blank">Layer</A>. <SPAN style="color: #3d3d3d; font-weight: 400;">Do I first need to create a Layer from the item and then add that to the web map maybe?</SPAN>

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Arne_Gelfert

Turns out the syntax of the ESRI example works when adding an item (as layer) to web map using add_layer() works when it was created as empty new web map like this:

webmap <SPAN class="operator token">=</SPAN> <SPAN class="token function">‍Webmap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

But not when the web map was created off another item and already has some layers...

webmap <SPAN class="operator token">=</SPAN> <SPAN class="token function">Webmap</SPAN><SPAN class="punctuation token">(</SPAN>item<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

This may be explained somewhere in ESRI documentation. Good to know!

Arne_Gelfert

This is Pro 2.5... I might try upgrading or at checking which version of arcgis modules my conda environment is using.

bixb0012

Since the Esri examples work for me in Jupyter, and I can't test directly using your data, I don't have any other suggestions/ideas at this point. Maybe a Pro version thing. What version of Pro are you running?

Arne_Gelfert

NewLayer is a Portal item that references a Map Service on our federated GIS Server. Where this all started was when I looked into copying a web map item from one Portal environment (Test) to another (Prod) and then trying to replace some map services .

bixb0012

Regarding newLayer_item, what exactly is it? I get the Esri examples to work in Jupyter, after a minor change to search outside my org, so I am wondering about your layer.

Arne_Gelfert

Jupyter Notebooks.

bixb0012

Where are you executing your code from, Python interactive windows in ArcGIS Pro, Python command prompt, Jupyter notebook?

Arne_Gelfert

So it looks like the following works:

newLayer_item <SPAN class="operator token">=</SPAN> gis<SPAN class="punctuation token">.</SPAN>content<SPAN class="punctuation token">.</SPAN>search<SPAN class="punctuation token">(</SPAN>query <SPAN class="operator token">=</SPAN> <SPAN class="string token">"new layer"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN>

<SPAN class="comment token">###############################################</SPAN>
<SPAN class="comment token"># the following line is new and made this work</SPAN>
newLayer <SPAN class="operator token">=</SPAN> arcgis<SPAN class="punctuation token">.</SPAN>gis<SPAN class="punctuation token">.</SPAN>Layer<SPAN class="punctuation token">(</SPAN>newLayer_item<SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token">###############################################</SPAN>
web_map_obj<SPAN class="punctuation token">.</SPAN>add_layer<SPAN class="punctuation token">(</SPAN>newLayer<SPAN class="punctuation token">)</SPAN>

<SPAN class="comment token"># Now I can see the new layers with</SPAN>
web_map_obj<SPAN class="punctuation token">.</SPAN>layers‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

Anyone know if the above referenced original ESRI example will ever work and if I was doing something wrong?

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