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I think you can just add the gaps as you want, the significance algorithm is quite robust. Regarding roughness for forest I would for sure not use a standard roughness of 0.5 m. That is generally too low in Europe, where a typical forest has h>10. The rule with z0=h*0.1 will give you usually a much better estimation. The displacement height is automatically calculated since WAsP Release 2022-A-1, if you specifiy them in a .gml file (you can use treeheight *(2/3), see paper I linked before). There is a video about using displacement heights and creating a GML file here: https://panopto.dtu.dk/Panopto/Pages/Viewer.aspx?id=0394a399-d5c2-4a71-9954-b0d800dbcb7f

Rogier, it would also be good to understand what gaps I can keep between for example forestry polygons, as this is often how they come in parcels of forestry with forestry access tracks between. I also feel the industry in general is using only 0.5 roughness length for forestry, as opposed to a roughness length relating to different tree heights. In some ways this also relates and depends on what displacement height is used? What is your view on these two approaches?

Yes exactly :)

Hi Rogier, Thanks for your answer and links to the articles. So I presume WAsP uses the speedups at different fixed heights from the cfdres files in order to get a better log profile and a better estimate of the geostrophic wind than with the IBZ model. Is this correct? Thanks!

WAsP CFD (I guess you are talking about the cfdres files) only calculates speedup factors from the terrain. There is no way to get from those files to a wrg file because that format also needs to know the wind distribution (e.g. frequency that the wind is blowing from a certain wind direction sector), which is not present in the cfdres files. So to get from those to the wind resource at 112 m, you will just need to run WAsP itself. That means it does all the steps in the generalization and downscaling of WAsP, using log profile, geostrophic drag law and stability effects. You can read more about those vertical and horizontal extrapolation steps in the European wind atlas and some more recent papers describing the stability model: https://backend.orbit.dtu.dk/ws/portalfiles/portal/112135732/European_Wind_Atlas.pdf https://link.springer.com/article/10.1007/s10546-023-00803-3

Hello, I need a wind resource grid (wrg) at 112m high (turbine hub height) as an input to Windfarmer. Wasp CFD calculates wind resource at fixed heights (5, 10, 20, 33, 48, 65, 80, 100, 120, 150, 200, 250 and 300 m). How is the mathematical process of interpolation from these fixed heights to the required wrg height within Wasp CFD? Thanks!

Thanks Rogier. This certainly shines a light on the subject. It would be great to get more of this info into the WAsP Help doc to better describe the limitations of WAsP, but appreciating the new developments.

These are some good questions and the exact behaviour depends also on WAsP version, as the roughness model has had some changes (mostly version Release 2022-A-1 as described here: https://www.wasp.dk/download/wasp12_releasenotes) If you are using WAsP from that version onwards it generates a zooming grid as a first step of processing a vector map. This is called spider grid analysis in this paper: https://wes.copernicus.org/articles/6/1379/2021/wes-6-1379-2021.html you can read more about how it works. It is probably most useful to look at Fig 2 there, which shows the spider grid analysis with the roughness lengths in all cells (2b) and the reduced number of roughness changes that is indeed 10 as you describe (2c). This is just to say that if there is a very small gap between polygons it will be aggregated anyway within a cell and it will not necessarily count as a change, because first a log averaged z0 weighted by landcover class areas in a cell is calculated. I copy the relevant part about the roughness reduction algorithm from this paper: https://wes.copernicus.org/articles/3/353/2018/wes-3-353-2018.pdf So in summary the both the distance to the roughness change and the change itself are important for the algorithm that selects the most significant roughness changes. It does not filter from the site outwards and stops when it has found 10 as you seem to think. It looks at all roughness cells simultaneously and also takes into account the distance to change. To some extent it can be problematic to have high-resolution maps of forested sites, because the few pixels with low roughness will lower the aggregated roughness quite a lot for WAsP (see Fig. 8 of the last mentioned paper), while in reality these pixels might even increase the effective roughness of a area due to additional form drag. For those cases it might make sense to use a higher roughness length then you would expect to alleviate this problem. But this is a different issue from which you are talking about, I think.

WAsP is limited to 10 roughness changes. The recommended size of a roughness map however, I believe is 20km by 20 km. In any case, with online sources of roughness, we often end up using polygons for things like forestry or water bodies, inside a background roughness. Polygons next to one another, which is the more accessible form of online mapping, gives twice as many roughness changes as single lines of roughness change (as intended in WAsP). In short with any sort of detail 10 roughness changes are arrived at very quickly and often quite near to the wind farm we are modelling. Are there any plans to increase the number of roughness changes WAsP can model, or are we better off using a smaller roughness map with the added detail. What is the guidance and where is the balance?

Thanks for taking the time to check my files. As you suggested I will surely try to get a updated version of map editor and see.

Thank you so much for the update. Your response was very helful to us. My understanding is weibull_combined function in https://docs.wasp.dk/windkit/_modules/windkit/weibull_wind_climate.html#weibull_combined gives us the sector combined shape and scale values along with that it calculates the 1st and 3rd moments. These are calculated by taking the sectowise A and k and sectowise wind frequency. I have few questions. I hope you would be kind enough to answer them. 1. What is in resource file? Is sectorwise A, k and wdfreq already present in resource file ? From where do we get the resource file ? 2. How is sectorwise A and k and sectorwise wind frequency calculated ? Is it provided by meterological stations directly? Do they have any software to calculate this? I tried to understand how this is calculated by referring to "European wind atlas" but was not able to get a clear picture of it. Thanks, Arya

Hi Shehan, I opened your files and couldn't see anything special about them. But I am on holiday and don't have the map editor on this computer. My only recommendation is to update your map editor versio, because there was numerous problems with that version of the map editor. I can look at it when I come back from holiday or otherwise write to the wasp support (see wasp.dk) if it is a urgent issue.

Thanks for your prompt reply and excuse me for late reply. My version of QGIS is 3.36.0-Maidenhead and MapEditor version is 12.3.1.54 Below are the intermediate files. GWA landcover polygons.gpkg https://drive.google.com/file/d/1HJxm-n90XZzQrc5isoBi6JqGX4Okn1MT/view?usp=sharing GWA landcover to roughness lines https://drive.google.com/file/d/15fzZSC96qrEP0_13W4yMDm4RdZ3IA1Oh/view?usp=sharing Best Regards Shehan

Hi Kwak, The error handling in WAsP software is implemented by try…except statements, see this site for explanation of the concept. When the computer is asked to do something impossible, it stops execution and raises an exception which the program can react to. There is also a basic message like “divide by zero”. A programmer which foresees all problems and spend sufficient time on error handling, might add comments like “Undefined hub height of Turbine no. 001”. However, most subroutines in the programs just raise a new exception and append more information about where the problem occurred. Subroutines can call each other in a long chain, so you often see a complicated message in the final report including information from all nested sub-routines. It is not particularly helpful for the end user, but it explains the fundamental error type, approximately where in the program the first exception was raised, and the last action in the user interface. Still it may not always enough to diagnose the problem, so we often ask for additional information like A test project file reproducing the problem A description of what you were trying to do, maybe supplemented by screen dumps A WAsP installation report You can save time if you include such information already the first time you contact WAsP support.

Dear Morten, Thanks for advices and guidances. I was hesitating to send email to the techincal team. however, it would be very helpful for us - End user - to make more intuitive error messages in the furture. the positions and coordinate systems had no issues as i checked every time. i have tried later in the evening and it worked. so my conclusion was that server went down temporarily. BR, Gyeongil

I tried to make a map for the same coordinates as you and I get more or less the same output but without errors. The spatial index warning you can ignore, this only has an impact on the speed, which is fast anyway. Can you share the intermediate layer that you get in QGIS? I.e. the "ESA-CCI landcover polygons" and "roughness lines" (right click, "Export > Save features as" and then save as .gpkg. And maybe you can also share your QGIS version (see "Help > About") and the map editor version? I am using QGIS v3.34.2. sadas.map

Hi Rogier, Thanks a lot for making this plugin available opensource. I encountered few issue when I tried to create roughness map files for an area in Tanzania with center coordinates ( -5.12238, 33.20613). After creating the bounding box and when downloading GWA landcover polygons. I saw below error in the box. https://drive.google.com/file/d/1y4eR_VEjIznPrXyGhDuB9K_MU40Hb6L3/view?usp=sharing My main concern is not that. Main concern is that the final WAsP roughness lines .map file when loaded into Map Editor gave me below errors. https://drive.google.com/file/d/16hfQwQrHMdbsoJglKkuOfz5AteE1QZgJ/view?usp=sharing https://drive.google.com/file/d/16r0AXqQUixh-1zSoUqkqyE-9kxe4-yJa/view?usp=sharing https://drive.google.com/file/d/1wqEWg5hVdjyN1EqY4sccbIjxdM_rBUed/view?usp=sharing When I view the roughness lines map it shows vertical lines as below. https://drive.google.com/file/d/1IXe5SxdiOy55u0R64-oO0_tPfjmFq1Xq/view?usp=sharing Looking forward to get this issue sorted with your help. Best Regards Shehan

You can see that in this code: https://docs.wasp.dk/windkit/_modules/windkit/weibull_wind_climate.html#weibull_combined It is getting the sector weighted first and third moments and does the weibull fitting with the method `_fit_k_sumlogm`

Thanks that was helpful. How is sectorwise A and k's, first and third moments calculated by NEWA

Creating good roughness and elevation maps is important for microscale flow modelling for wind resource and siting assessment. The WAsP scripting plugin can help with this and is now available for installation via the official QGIS plugin channel. You can just go the Plugins > Manage and install plugins and search for "WAsP scripting". The plugin contains scripts for: Downloading elevation data Downloading landcover data Convert landcover polygons to roughness or landcover lines as required by WAsP Creating hand digitized landcover polygon maps Saving the elevation, roughness or landcover lines as WAsP .map/.gml files Video solutions for different work flows are available in this playlist It contains a general introduction to QGIS for WAsP applications and some more specific video tutorials on the different workflows for which the scripts can be used and some pitfalls to be aware of when using these scripts. Specific tutorials Importing an elevation map from the GWA warehousee creating a hand-digitized landcover map using google earth satellite data Import a landcover map from the CORINE database

The two most common problems with the SCM tool are The SCM server providing the long-term reference data might be down. However, I just checked and it worked OK this afternoon. If the coordinates of the reference mast or the map projection are incorrect, the SCM server might not find the data, e.g. it if the false position is in the middle of an ocean. The easiest way to check the mast location is to open a spatial view, synchronize with Google Earth (see below), and make sure that the map is displayed correctly on the virtual world. If these simple explanations does not apply, then please contact our technical support system via mail. The above error message might be enough for the programmer to understand the issue, but please also describe your actions just before the error message arrived. Screen dumps and a sample project file demonstrating the problem are also useful and sometimes even necessary. In general, it is usually better to contact the support system about specific technical problems and reserve this forum for discussions of interest to all users.

Dear Team, I am trying to compare the results between EWC and SC method but i could not run SC method. i tried to change the map size, map file, and wind data as well. however, nothing works. the message is as follows but hard to interpret. // Exception report produced at 2024-06-21 17:47:47 Object variable or With block variable not set raised at: 2024-06-21 17:46:12 2024-06-21 17:46:12: Message added: Could not create a SCM data server 2024-06-21 17:46:12: Message added: Could not begin the insertion of an SCM extreme wind climate 2024-06-21 17:46:12: Exception raised in: WAsP Engineering: cProjectEditor:InsertingScmExtremeWindClimateBegin 2024-06-21 17:46:12: Message added: Could not explore (or perform one of) the operations available for a selected thing 2024-06-21 17:46:12: Exception raised in: WAsP Engineering:cOperationSet:ExploreOperations 2024-06-21 17:46:12: Message added: The 'Create generalised extreme wind climate using SC method' operation could not be performed 2024-06-21 17:46:12: Exception raised in: WAsP Engineering:cOperation:Invoke 2024-06-21 17:46:12: Message added: Could not perform the action requested 2024-06-21 17:46:12: Exception raised in: WAsP Engineering:cMainform:ProcessContextMenuToolClick Latest thread started in: WAsP Engineering:cMainform:pSlaveForm_ToolbarClicked // could you please help me out to progress? Regards, Gyeongil

We have released new versions of PyWAsP and Windkit. Windkit has a number of deprecations, please pay attention if you are using these. We aren't sure how long we should keep deprecations around, please let us know if you have thoughts on this. PyWAsP has a number of breaking changes, we are closing in on a more stable API, but still expect a few more breaking changes. The highlights of Windkit include a new Long Term Correct module, an improved WindTurbines class, better integration with GeoPanandas, Improvements to downloading of raster and vector maps, and a new function to implement cross prediction. Full release notes can be found at: https://docs.wasp.dk/windkit/release_notes.html#id1 For PyWAsP the main highlight is the new climate extrapolation functions. These functions allow the prediction of either binned or weibull wind climates without creating a generalized wind climate lookup table, reducing interpolation errors. The binned wind climate to binned wind climate approach was presented at the Wind Europe Technical Workshop for Resource Assessment. In addition, new BWC resampling functions have been added, we have included support for custom root CA certificates, and have been able to improve performance for a number of functions. Full release notes are found at: https://docs.wasp.dk/pywasp/release_notes.html#id1

Yes that calculation is similar except you don't need the fgtm (frequency greater than mean) variable, because the inputs for NEWA microscale are sectorwise A and k's, the fgtm is only required when you have a wind speed histogram as input. The first and third moments are calculated from the wind direction frequency weighted first and third moments and then you can use `_fit_wasp_m1_m3` to find the combined A and k from those.

Thank you so much. I was specifically looking for the calculation of weib_A_combined and weib_k_combined values which is obtained from downloading the wind data from Microscale API https://wps.neweuropeanwindatlas.eu/api/microscale-atlas/v1/get-data-bbox. Do they use https://docs.wasp.dk/windkit/_modules/windkit/weibull.html#_fit_wasp_m1_m3_fgtm as well for the calculation of weib_A_combined and weib_k_combined ?