Ole Rathmann

Hi Madelena Ferreira, sorry about your problems with the roughness shape-file input. I cannot tell right away what is wrong - I would need to have your problematic shape-file to look at. So, could you please send me the shape-file? Just use my e-mail address olra@dtu.dk. Ole Rathmann

Hi Gaoithe, apparently a wrong SRTM URL-address was used. Glad the problem is solved. Ole Rathmann

Hi, when you start from scratch you must - in addition to adding fixpoints for your background map (in your case: a *.jpg picture), also define the boundaries the map domain. You do that by the menu-option "File | Load Empty Map" or "Edit | Adjust Map Domain Size". Then you will be able to perform digitzing within the specified domain boundaries.

Dear Alex, I can give you an answer re. the Geo-referencing format used by the WAsP applications: WAsP Map Editor and WAsP itself. Your examples File2.map .. File5.map have apparently not been produced by these applications. When saved by the Map Editor the header-line looks like this: +Waspdale10 - webs-test | UTM-N Z31 WGS-8|WME ver. 11.22.1.29 So here "block2", between the first and the second bar-character, contains the projection specification: the projection type, the zone specification (if a zone is needed) and the datum-specifcation; here WGS-8 is the code for "WGS 84". Block 3 has nothing to do with the geo-reference: it specifies the version of the Map Editor that produced the map file. When exported by WAsP itself the header-line looks like this (one long line): + 'Canela' (WAsP export) 'Canela Terrain' | UTM-S Zone 19 (WGS 1984 datum) Again, block 2 specifies the projection; the datum is here specified in parenthesis after the zone specification. Hope this explanation is helpful.

Hi - combining two digital maps in the Map Editor is quite easy: You load the first map using the File|Open menu-option, and after that you load the second digital map using the "File | Add" or "File | Add-and-Replace" option, the latter if the second map overlaps the first map and is ment to replace it in the overlapping area. Once the combination of the two maps has been performed you may simply save the combined map. For this operation no WAsP licence is needed - the Map Editor is freeware. /Ole Rathmann Regards

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

Hi Javo Cord - correct! WAsP10.2 does not any longer support use of displaying stuff in Google Earth. - since Google has stopped supporting the interface WAsP 10 was created for. However, WAsP 11 supports the new way of programmatic communication with Google Earth!! So all your WAsP-GoogleEarth troubles will be goen if you upgrade to latest version of WAsP11 .. /Ole Rathmann

Hi Marco - you are posing a tricky question! It is in fact possible to use WAsP to get an estimate of the speed-reduction due to the wake from the wind farm in dependence of wind direction, but it is a somewhat cumbersome. You would need, in a special WAsP-project, to set up the wind farm, using the actual power curve of the turbines; and then add an additional "virtual" turbine to represent the met-mast, i.e. with the location of the met-mast and the hub-height=met-mast measuring height. However, this virtual turbine should have its own, very special power-curve object (WTG): the Ct-should be = 0 for all wind speeds, and the power curve should be a "fake" one: it should be completely linear over a large speed-span, e.g. (0 for 0 m/s), (50 for 50 m/s). You could use any OWC to define the generalized wind climate of the "special" WAsP project, as long as it is well-behaved in all sectors: having a non-zero frequency and a histogram with a decent mean wind speed, e.g. 8 m/s. The resulting wake effect for the virtual turbine, in dependence of wind direction, would then give the average speed-reduction due to the wake effect from the true turbines. I have written "average" since the wake effect will in fact be speed dependent since the Ct-coefficient for the true turbines depends on the speed. This way you should have numbers for the speed reduction at your met-mast site. Now, in your true Wasp project, you should then apply these speed reductions as negative user corrections for the met-mast: if in sector 1 the speed reduction (due to wakes) was found to be 5% you should then specify a user-correction of -5 for sector 1. Same thing for the remaining directions. Good luck! Ole Rathmann.

Hi, "ichadtanguilig" (what ever that means?) - unfortunately the WAsP suite does not support all digital map formats, in this case the Aster GDEM. But - as an alternative - the Map Editor may import SRTM maps (version2, 3-arc-sec resolution; up to 60 deg. North). For Aster GDEM We could suggest to use a) Global Mapper to convert to WAsP .map, or b) Surfer: here should google for "Aster GDEM to Surfer" to find a solution to make Surfer read Aster GDEM, since Surfer cannot do it directly; afterwards have Surfer export the map-contours as a DXF-file, which the Map Editor may then read - and then save as .map. Both Global Mapper and Surfer are commercial products. Finally we could suggest to try the free-wares c) SAGA GIS and d) QGIS: they may be able to read GDEM and convert directly to .map or another vector format which may be imported by the Map Editor, and then saved as .map. Regarding .map and Wind Farmer: you will have to contact the Wind Farmer people directly. The .map format is well described in the WAsP Map Editor - so it should be straight-forward to check whether Windfarmer can accept that. Ole Rathmann

Hi "kedx3mmn" - I have a feeling that I have already answered you - but anyhow! You don't need to use BOTH WindPro and WAsP to run energy simulations, WAsP alone can do the job. About the allowable size of maps: WAsP itself has no limitations regarding how large (comprehensive) a terrain map you use for the terrain around your wind farm. Normally we recommend 5km, or 10 km to be sure, in any direction from any of the turbines or the met-mast. If the met mast is located a long distance (say 20 km) from the wind farm, the met mast could have its own map, say 10x10 km, or better: 20x20 km with the met-mast location in the centre. The Map Editor allows you to get a DEM-map from SRTM-data at a size required by the WAsP project - the Map Editor itself will not restrict the size of the DEM-map. /Ole Rathmann

Hi Stefano, re. the error message when AveragingTimeRecordingInterval : I will report the error to the proper programmer. But you should not bother, just use, as you have already tried - AveragingTime=RecordingInterval: it has - for the moment - not effect on average and extreme wind climates. "Unsuccessful Analysis" when calculating an OEWC-POT means that your observed extreme winds (ranked) are not distributed like expected. Could happen if you use too short time series. You may still be able to use it, however, but with increased uncertainty. Using two maps: When calculating the average wind climate at site B from the measured data at site A: Associate the map around site A directly with the met-station (at site A) or with the generalized wind climate object - and the map around site B with the project object. When calculating the extreme wind climate at site B from the measured data at site A (using WAsP Engineering): If you are not able to combine Maps A and B you will have to perform the calculation I two steps: Step 1: Calculate the generalized extreme wind climate from the observed extreme wind climate at A - using map A; and save the generalized extreme wind climate. Step 2: In a new WAsP Engineering project, with Map B, include the aforementioned generalized extreme wind climate, and then calculate the extreme wind climate at site B. Ole.

Hi - first: You can certainly make 1st class wind energy simulations using WAsP alone. Windpro is a different piece of Wind Resource software - but it uses the WAsP flow model as its modeling engine. Both softwares have automated facilities to get topographical maps from SRTM. The difference may be regarding the latest, high-resolution versions of the SRTM maps: in WAsP we have not yet upgraded the automated SRTM import facility to also include the latest high-resolution versions of SRTM-maps - but we will in the near future.

Sorry Neil - I thought you were talking about WAsP 11.2. However, I have just checked the latest WAsP10.2 (10.02.0017) - and the CTRL+C copying option works in relation with the Wind Farm Power curve: Point into the wind farm power curve window, type CTRL+C and you should see a small yellowish notifier-label saying the content has been copied to the clip-board. Ole Rathmann

Hi Neil - it seems that the copy-option somehow dropped out in version 10.2. However, it works fine in the latest version, 10.4 - so just update your WAsP installation. Ole Rathmann

Hi "vob" - agree that this looks mysterious. First, please make sure that the reference mast is located at the same position as the turbine and has the same height as the hub-height of the turbine - otherwise you cannot make that comparison. If nothing is wrong there we need to have your workspace to solve the case. So in that case I invite you to send the case and the workspace to us on WASPSUPPORT@dtu.dk, full confidentiality of course - and we will find out what is the matter. Ole Rathmann