Build Virtual Vector tool: file created fails to load correctly

[qgib]

Author Name: Armando Forlani (Armando Forlani)
Original Redmine Issue: 14374
Affected QGIS version: 2.12.0
Redmine category:processing/qgis

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This is either Build Virtual Vector tool not creating the correct xml or QGIS not interpreting it (the correct xml?) correctly.

I have tested this real world scenario: shape files of identical names.

'\\..\data\folderA\osm_roads.shp' contains a small bbox selection of central London OSM roads
'\\..\data\folderB\osm_roads.shp' contains a small bbox selection of central London OSM roads

The two shape files do not contains the same osm extent, they are adjacent (almost). They are of the same file name but two distinct tiles (different bbox extents).

├ data
│ ├ folderA
│ │ └ osm_roads.shp
│ ├ folderB
│ │ └ osm_roads.shp

Build virtual vector should create a combination (union?) of the two tiles.

Zip file attached containing files, folder structure and results.

sequence:

1. Launch 'Build virtual vector'
2. 'Run as Batch process...'
3. Remove parameters row. Only one is needed here
4. Select 'Input datasources' --> 'Select from filesystem'
5. Use the search functionality offered by your OS to select the (only two) osm_roads.shp files from the parent folder (\\..\data\)
6. Name the virtual vector (\\..\data
   oads)
7. Do the same with a different virtual vector file name (\\..\data
   oads_)
8. Run
9. Open virtual vector
10. 'Select all' from the 'Select vector layers to add...' form and click ok

Notes:
Step 2 should not be necessary in this context. 'Input datasources' box does not allow for file system selection. 'Run as batch process...' does.
Step 5 this is necessary in a real world scenario: hundred of folders exist.
Step 7 it is necessary as this is a "batch processing" (although in this case it's only a work around, not batch processing as such)
Step 10 As expected the Layer name(s) are the same: osm_road but clearly two different vector layers, the Number of features indicates so (different feature counts)

Issues:
(0. File extension is missing on the Virtual vector file '\\..\data
oads and \\..\data
oads2' it opens anyway, not really an issue, only for correctness)

1. Instead of the two adjacent tiles the same one tile (\\..\data\folderA\osm_roads.shp) is displayed twice.

This is odd. The actual resulting virtual vector file '\\..\data
oads' seems to contain the correct xml declarations:

\\..\data\folderA\osm_roads.shp
\\..\data\folderB\osm_roads.shp

The xml seems correct but somewhat QGIS interprets it wrongly.

Tested with QGIS 2.12.0 on win 7 and Ubuntu 14.04

Notes:
In a hipothetical scenario such as this (which I also tested):

├ data
│ ├ folderA
│ │ └ osm_roads1.shp
│ ├ folderB
│ │ └ osm_roads2.shp

Not only the folders are of different names (as in my real world example above) but also the shape files are of different names.

Build virtual vector --> roads12

The resulting virtual vector:
\\..\data\folderA\osm_roads1.shp
\\..\data\folderB\osm_roads2.shp

..it is interpreted correctly by QGIS and the two files display correctly i.e. two adjacent tiles.

---

• data.zip (Armando Forlani)

[qgib]

Author Name: Alexander Bruy (@alexbruy)

---

• category_id was configured as Processing/QGIS

[qgib]

Author Name: Giovanni Manghi (@gioman)

---

• easy_fix was configured as 0
• regression was configured as 0

[qgib]

Author Name: Alexander Bruy (@alexbruy)

---

Works fine in master. Please reopen if necessary.

---

• resolution was changed from to worksforme
• status_id was changed from Open to Closed
• description was changed from This is either Build Virtual Vector tool not creating the correct xml or QGIS not interpreting it (the correct xml?) correctly.

I have tested this real world scenario: shape files of identical names.

'\\..\data\folderA\osm_roads.shp' contains a small bbox selection of central London OSM roads
'\\..\data\folderB\osm_roads.shp' contains a small bbox selection of central London OSM roads

The two shape files do not contains the same osm extent, they are adjacent (almost). They are of the same file name but two distinct tiles (different bbox extents).

├ data
│ ├ folderA
│ │ └ osm_roads.shp
│ ├ folderB
│ │ └ osm_roads.shp

Build virtual vector should create a combination (union?) of the two tiles.

Zip file attached containing files, folder structure and results.

sequence:

1. Launch 'Build virtual vector'
2. 'Run as Batch process...'
3. Remove parameters row. Only one is needed here
4. Select 'Input datasources' --> 'Select from filesystem'
5. Use the search functionality offered by your OS to select the (only two) osm_roads.shp files from the parent folder (\\..\data\)
6. Name the virtual vector (\\..\data
   oads)
7. Do the same with a different virtual vector file name (\\..\data
   oads_)
8. Run
9. Open virtual vector
10. 'Select all' from the 'Select vector layers to add...' form and click ok

Notes:
Step 2 should not be necessary in this context. 'Input datasources' box does not allow for file system selection. 'Run as batch process...' does.
Step 5 this is necessary in a real world scenario: hundred of folders exist.
Step 7 it is necessary as this is a "batch processing" (although in this case it's only a work around, not batch processing as such)
Step 10 As expected the Layer name(s) are the same: osm_road but clearly two different vector layers, the Number of features indicates so (different feature counts)

Issues:
(0. File extension is missing on the Virtual vector file '\\..\data
oads and \\..\data
oads2' it opens anyway, not really an issue, only for correctness)

1. Instead of the two adjacent tiles the same one tile (\\..\data\folderA\osm_roads.shp) is displayed twice.

This is odd. The actual resulting virtual vector file '\\..\data
oads' seems to contain the correct xml declarations:

\\..\data\folderA\osm_roads.shp
\\..\data\folderB\osm_roads.shp

The xml seems correct but somewhat QGIS interprets it wrongly.

Tested with QGIS 2.12.0 on win 7 and Ubuntu 14.04

Notes:
In a hipothetical scenario such as this (which I also tested):

├ data
│ ├ folderA
│ │ └ osm_roads1.shp
│ ├ folderB
│ │ └ osm_roads2.shp

Not only the folders are of different names (as in my real world example above) but also the shape files are of different names.

Build virtual vector --> roads12

The resulting virtual vector:
\\..\data\folderA\osm_roads1.shp
\\..\data\folderB\osm_roads2.shp

..it is interpreted correctly by QGIS and the two files display correctly i.e. two adjacent tiles. to This is either Build Virtual Vector tool not creating the correct xml or QGIS not interpreting it (the correct xml?) correctly.

I have tested this real world scenario: shape files of identical names.

'\\..\data\folderA\osm_roads.shp' contains a small bbox selection of central London OSM roads
'\\..\data\folderB\osm_roads.shp' contains a small bbox selection of central London OSM roads

The two shape files do not contains the same osm extent, they are adjacent (almost). They are of the same file name but two distinct tiles (different bbox extents).

├ data
│ ├ folderA
│ │ └ osm_roads.shp
│ ├ folderB
│ │ └ osm_roads.shp

Build virtual vector should create a combination (union?) of the two tiles.

Zip file attached containing files, folder structure and results.

sequence:

1. Launch 'Build virtual vector'
2. 'Run as Batch process...'
3. Remove parameters row. Only one is needed here
4. Select 'Input datasources' --> 'Select from filesystem'
5. Use the search functionality offered by your OS to select the (only two) osm_roads.shp files from the parent folder (\\..\data\)
6. Name the virtual vector (\\..\data
   oads)
7. Do the same with a different virtual vector file name (\\..\data
   oads_)
8. Run
9. Open virtual vector
10. 'Select all' from the 'Select vector layers to add...' form and click ok

Notes:
Step 2 should not be necessary in this context. 'Input datasources' box does not allow for file system selection. 'Run as batch process...' does.
Step 5 this is necessary in a real world scenario: hundred of folders exist.
Step 7 it is necessary as this is a "batch processing" (although in this case it's only a work around, not batch processing as such)
Step 10 As expected the Layer name(s) are the same: osm_road but clearly two different vector layers, the Number of features indicates so (different feature counts)

Issues:
(0. File extension is missing on the Virtual vector file '\\..\data
oads and \\..\data
oads2' it opens anyway, not really an issue, only for correctness)

1. Instead of the two adjacent tiles the same one tile (\\..\data\folderA\osm_roads.shp) is displayed twice.

This is odd. The actual resulting virtual vector file '\\..\data
oads' seems to contain the correct xml declarations:

\\..\data\folderA\osm_roads.shp
\\..\data\folderB\osm_roads.shp

The xml seems correct but somewhat QGIS interprets it wrongly.

Tested with QGIS 2.12.0 on win 7 and Ubuntu 14.04

Notes:
In a hipothetical scenario such as this (which I also tested):

├ data
│ ├ folderA
│ │ └ osm_roads1.shp
│ ├ folderB
│ │ └ osm_roads2.shp

Not only the folders are of different names (as in my real world example above) but also the shape files are of different names.

Build virtual vector --> roads12

The resulting virtual vector:
\\..\data\folderA\osm_roads1.shp
\\..\data\folderB\osm_roads2.shp

..it is interpreted correctly by QGIS and the two files display correctly i.e. two adjacent tiles.