import .shp files to WME

[asela115]

Hi,
I have Arcgis shape file having polygons with corresponding landuse IDs in its attribute table. When importing .shp file, MapEditor asks for internal and external roughness values.

It is possible to assign an internal roughness value for each polygon, but assigning external roughness value is difficult for a larger map. There are many cases where polygons are interfacing with multiple different other landuse types (which are having different roughness values). So external roughness value is also varying.Just assigning a internal roughness value only and importing to MapEditor gives so many crosspoint errors.

Is there a better approach when dealing with .shp files (rather than manually digitizing a larger map within MapEditor)

Thanks

[Ole Rathmann]

Hi (whoever you are) - I agree importing shape-files into the Map Editor for roughness lengths by polygons is problematic. I guess the bottleneck is really the cross-point errors, which is caused by overlapping line-segments of neighbouring polygons. The Map Editor is not sufficiently smart to see that these lines segments only touch but do not cross. How to work around? Well, do you have any possibility to change the polygons so that a a tiny space (a fraction of a meter) is left between them? Then it would be possible - although tedious - to add the necessary external roughnesses ...
Another solution requires a bit of patience. We are just now finishng a new Map Editor version which is able to accept "unknown roughness" specification for e.g. external roughness of a polygon. The new Map Editor is - in the process just after reading - able to infer the missing roughness lengths from neighboring or surrounding roughness-change lines. But it would still require you to adjust the polygons to avoid overlapping. Another new feature is grid-file importing. So if you could convert the shape-file to a grid file (Surfer ASCII .grd format) the new map editor version would be able to read that right away - and convert it to a standard WAsP .map file.
/Ole Rathmann

[Antonio]

Hi, was this function implemented?

We actually have a very good roughness map in shape file, and we would like to import it in Map Editor. We succeeded in importing the polygons but not the roughness values. I guess the problem is that the shape file contains / export only one z0 (not the left/right). Do you think we could try to export it in ASCII shape format, and modify with a macro by adding a right z0" value = "unknown roughness"? Do you think in this way it could work? Alternatively is it possible that we send to you the shape file and you try to convert it to .map?

thank you

best regards

Antonio

[Rogier]

Hi Antonio,

There is some experimental helper scripts in the free software QGIS attached. You can install these files per the instructions in the attached document and then look for a script called 'Polygons to roughness lines'. The instructions attached are for a new release of WAsP that can deal with displacement height, but if you are dealing with roughness length you only need the 'z0' field. So to save a WAsP .map file you will need to use the script 'Save WAsP roughness layer' instead of the 'Save WAsP landcover layer' that is described in the document.

Regards

All files are in this folder:

https://data.dtu.dk/articles/software/Using_QGIS_to_create_WAsP_maps/20495178

• The experimential helper scripts are called "wasp_scripts.zip" (installation instructions in the documents below)
• A full workflow to make both elevation and roughness maps in QGIS is included in "Creating a WAsP elevation and roughness map using QGIS"

Edited September 20, 2023 by Rogier

[Gururaj]

On 30/11/2021 at 2:39 PM, Rogier said:

Hi Antonio,

There is some experimental helper scripts in the free software QGIS attached. You can unzip these file per the instructions in the attached document and then look for a script called 'Polygons to roughness lines'. The instructions attached are for a new release of WAsP that can deal with displacement height, but if you are dealing with roughness length you only need the 'z0' field. So to save a WAsP .map file you will need to use the script 'Save WAsP roughness layer' instead of the 'Save WAsP landcover layer' that is described in the document.

Regards

QGIS_GML.pdf 5 MB · 4 downloads QGIS_WAsP_scripts.zip 39 kB · 4 downloads

Hi Antonio, 

I thank you for your very clear explanantion in the document provided. But i face an issue when i try to extract the roughness infomation to my buffered sqaure cut out. When i hit run for the processing, i get this error in the log box stating : 

CRS is EPSG:3857

Clipping to Input Polygon...

Results: {'OUTPUT': 'Buffered_926a48a4_1e94_4c2e_860c_b8148151f2da'}

Clipping to bounding box...

Results: {'OUTPUT': 'Clipped_9c48318d_1528_497d_a078_00adafb7ec47'}

Clipping to Input Polygon...

Results: {'OUTPUT': 'Reprojected_3457eeea_60a7_4089_9aea_410a0a3ef6f8'}

Joining CORINE roughness table

Invalid join fields

Execution failed after 0.79 seconds

 

for your reference the steps i am stuck at comes in page 7 of your document. Can you please help me resolve the issue. I am looking for location 

 UTM WGS 84 Zone 34 - 505655.34 E, 4458722.16 N

BR,

 

[Rogier]

Hi Gururaj,

My best guess is that you didn't unpack the file CORINE.gpkg from the ZIP file. That also has to be in the script directory as explained on page 2. 

Regards

Rogier

[Gururaj]

25 minutes ago, Rogier said:

Hi Gururaj,

My best guess is that you didn't unpack the file CORINE.gpkg from the ZIP file. That also has to be in the script directory as explained on page 2. 

Regards

Rogier

Hi Rogier,

Thank you so much for your response. There was an issue with the folder path. I could successfully create the .gml file. But when i try to read import the .gml file in WAsP. it gives this error 

Exception report produced at 2022-01-04 12:01:42

There is no child element with name: "wasp-chg:AerodynamicalRoughnessLength raised at: 2022-01-04 12:01:37
    2022-01-04 12:01:37: Exception raised in: Rvea0254:cVectorMapGmlFilter:GetFirstImmediateChildElementOfName
    2022-01-04 12:01:37: Message added: Could not restore a map from GML file
    2022-01-04 12:01:37: Exception raised in: Rvea0254:cVectorMapGmlFilter:RestoreMapFromFile
    2022-01-04 12:01:37: Message added: Could not restore the map from file
    2022-01-04 12:01:37: Exception raised in: Rvea0254:cVectorMap:RestoreFromFile
    2022-01-04 12:01:37: Message added: Failed to restore map instance
    2022-01-04 12:01:37: Exception raised in: Rvea0254:VectorMapClass:RestoreInstanceFromFile
    2022-01-04 12:01:37: Message added: Could not open a vector map from data file
    2022-01-04 12:01:37: Exception raised in: Rvea0334:cVectorMap:OpenDataFile
    2022-01-04 12:01:37: Message added: Could not insert a Vector map from file 'pk' to the hierarchy
    2022-01-04 12:01:37: Exception raised in: Rvea0334:cHierarchyInsertionFromFile:InsertFromFile
    2022-01-04 12:01:37: Message added: There was a problem with the insertion
    2022-01-04 12:01:37: Exception raised in: WAsP:cWorkspaceController:ExecuteHierarchyInsertion
    2022-01-04 12:01:37: Message added: The insertion was not successfully completed
    2022-01-04 12:01:37: Exception raised in: WAsP:cMemberPopupMenuMediator:ProcessInsertionFromMenu
    Latest thread started in: Wiab0001:fInteractionPointQuestion:Form_QueryUnload

 

I also tried to open the file in WAsP map editor with the options "file -> Open WAsp GML". Even there it reads out error. I could exactly follow all the steps till the end except the reading the file in WAsP software. Please guide me further to resolve the issue

Thank you for your time.

 

 

[Gururaj]

Hi Rogier,

The map does not open in WAsP 12.6. I updated the software to 12.7 and the file works in the latest verison (2022). Thanks for the support.

Best Regards,

Gururaj

[Rogier]

Yes  these new GML files can contain displacements heights, which is a feature which is only available from WAsP 12.7 onwards. But I am happy you got it to work.

[Gururaj]

Hi Rogier, 

Do you also have any some experimental helper scripts for creating the orography layer for WAsP in QGIS? With the latest version of WAsP map editor i am unable to import the SRTM elevation data format .hgt (https://dwtkns.com/srtm30m/) into the map editor for contouring nor i am able to readily download the data from the GWA warehouse because of the URL issue. I would like to have a WAsP GML layer for orography,  in the similar process as you have done it for landcover. 

Please suggest me a better way to obtain the orography layer for the site assessment. 

[Rogier]

Hi,

Yes coincidentally I just gave a course with that. You will need the same scripts as I included above. I copy the instructions below:

https://data.dtu.dk/articles/software/Using_QGIS_to_create_WAsP_maps/20495178

There is a video how-to here:

https://panopto.dtu.dk/Panopto/Pages/Viewer.aspx?id=f855a532-b99c-44af-b105-b08300954b2d

You may also need the introduction to QGIS to give some background:

https://panopto.dtu.dk/Panopto/Pages/Viewer.aspx?id=870b0413-4956-4b3f-a9b2-b0830094e790

Edited September 20, 2023 by Rogier

[Gururaj]

Hi Rogier,

Thank you very much for the clear instructions. I could successfuly create the elevation map file with the above instruction for my desired site.

I am concerned about the displacement height. If I have a wind farm at the mountain ridge and I have forest all along the slope of the mountain ridges. Does the concept of displacement height still apply? Also, Will the dispalcement height (if it applies) be automatically added as per the instruction in QGIS_GML (helper scripts) at the end or do I need to manually calculate and specify in the landcover table for a close location to the wind farm using the ID's ? 

If it's manual, can I use the forest canopy height value suggested by the website (https://glad.earthengine.app/view/global-forest-canopy-height-2019)  and take a mean height value for the forset around the wind farm as the input parameter to find the displacement height and roughness length (displacement = (2/3)*tree height and roughness = 0.1*tree height ?

Is it necessary that i need to edit the roughness length values ? since i get the roughness length values autogenerated from the CORINE database? Will it imapct significantly in the Wind resource assessment ?

 

Your guidance would be really appreciated. 

Thank you very much for your time,

Best Regards,

Gururaj

[Rogier]

Hi,

Yes that is a rather tricky situation. Regardless what you do you will probably have high flow-modelling uncertainty with a forest on a hill. Using the CORINE data you will have to add a displacement height, that is not done automatically because it depends on the height of the forest. You can try to use those global forest data to estimate a forest height, but I don't have experience with that myself. If you really want an accurate forest height you can in some countries download data from lidar scans (e.g sweden, denmark, finland). If you have lidar data you can also separate the orography and roughness better, because SRTM data include to some extent the tree heights within the elevation data because they are measured by satellite (i.e. it is a digital surface model and not a digital terrain model). 

If your wind farm is directly in the forest the displacements will for sure have big impact. If they are further away it is mostly the roughness that will have a impact.

Some more links regarding forest modelling and WAsP:

https://wes.copernicus.org/articles/6/1379/2021/

https://wes.copernicus.org/articles/3/353/2018/

Regards

Rogier

 

Edited January 12, 2022 by Rogier

[Alfonso]

On 30/11/2021 at 2:39 PM, Rogier said:

Hi Antonio,

There is some experimental helper scripts in the free software QGIS attached. You can install these files per the instructions in the attached document and then look for a script called 'Polygons to roughness lines'. The instructions attached are for a new release of WAsP that can deal with displacement height, but if you are dealing with roughness length you only need the 'z0' field. So to save a WAsP .map file you will need to use the script 'Save WAsP roughness layer' instead of the 'Save WAsP landcover layer' that is described in the document.

Regards

QGIS landcover instructions (pdf)

https://files.dtu.dk/u/1j9mfoS_ZkDEP2Z-/bdb0dbc2-fbb7-4755-81fb-b353f24d3942?l

WAsP scripts (zip)

https://files.dtu.dk/u/4g0MU7CNDG_wDQxT/b01717a6-963c-44a4-beea-98f15ca26174?l

 

Hi Rogier,

I tried to download the script and relative instruction but I received the following error message: "Could not find shared item. It has been either moved or deleted, or the link has expired."

Could you help me?

Thanks

Alfonso

[Rogier]

Hi Alfonso,

Yes for some reason the permissions had changed. I have updated the link above now. There is also some new instruction videos added.

Regards