make mesh_dir behavior consistent across create_meshing_tasks and cre…

…ate_mesh_manifest_tasks (#178)

* typo fix in README, remove duplicate arguments in skeletonization example

* make mesh_dir behavior consistent across create_meshing_tasks and create_mesh_manifest_tasks

* fix vol.mesh.get in bounds_from_mesh

README.md

@@ -458,7 +458,7 @@ tasks = create_meshing_tasks(             # First Pass
 tasks = create_mesh_manifest_tasks(layer_path, magnitude=3) # Second Pass
 ```
 
-The parameters above are mostly self explainatory, but the magnitude parameter of `create_mesh_manifest_tasks` is a bit odd. What a MeshManifestTask does is iterate through a proportion of the files defined by a filename prefix. `magnitude` splits up the work by 
+The parameters above are mostly self explanatory, but the magnitude parameter of `create_mesh_manifest_tasks` is a bit odd. What a MeshManifestTask does is iterate through a proportion of the files defined by a filename prefix. `magnitude` splits up the work by
 an additional 10^magnitude. A high magnitude (3-5+) is appropriate for horizontal scaling workloads while small magnitudes 
 (1-2) are more suited for small volumes locally processed since there is overhead introduced by splitting up the work.  
 
@@ -515,8 +515,6 @@ tasks = tc.create_skeletonizing_tasks(
     dust_threshold=1000, # Don't skeletonize below this physical distance
     progress=False, # Show a progress bar
     parallel=1, # Number of parallel processes to use (more useful locally)
-    spatial_index=True, # generate a spatial index for querying skeletons by bounding box
-    sharded=False, # generate intermediate shard fragments for later processing into sharded format
     cross_sectional_area=False, # Compute the cross sectional area for each vertex.
     cross_sectional_area_smoothing_window=5, # Rolling average of vertices.
   )

igneous/task_creation/mesh.py

@@ -168,7 +168,10 @@ def create_meshing_tasks(
   vol = CloudVolume(layer_path, mip)
 
   if mesh_dir is None:
-    mesh_dir = 'mesh_mip_{}_err_{}'.format(mip, max_simplification_error)
+    if 'mesh' in vol.info:
+      mesh_dir = vol.info['mesh']
+    else:
+      mesh_dir = 'mesh_mip_{}_err_{}'.format(mip, max_simplification_error)
 
   if not 'mesh' in vol.info:
     vol.info['mesh'] = mesh_dir

igneous/task_creation/skeleton.py

@@ -48,8 +48,9 @@ def bounds_from_mesh(
   """Estimate the bounding box of a label from its mesh if available."""
   bbxes = []
   for label in labels:
-    mesh = vol.mesh.get(labels)[label]
-    if mesh is None:
+    try:
+      mesh = vol.mesh.get(label)
+    except ValueError:
       raise ValueError(f"Mesh {label} is not available.")
 
     bounds = Bbox.from_points(mesh.vertices // vol.resolution)