Support FAQ

How do I add turbines in openWind?

Just right-click in the left-hand panel and choose New Layer. Then choose Turbine Layout from the next pop-up. This will add a Site Layer in the left hand panel. You can now add turbines by editing the layer and right-clicking in the map view to add a turbine.
You can also add turbine to the site layer by right-clicking on the Site Layer and choosing Properties then moving to the Turbine Coordinates tab and using the Autoplace option or by pasting in turbine coordinates from a spreadsheet program.

How do I edit a layer?

First select the layer you want to edit in the left hand panel. Now click the toolbar button which looks like an arrow pulling a squiggly line. This is the edit button. Once you have done this and are in edit mode (signified by the edit button being in the pressed position) you can move points by left-clicking and dragging them or you can insert new points by right-clicking. Pressing the Delete key will delete that last selected point.
When editing lines or polygons, holding down the Shift key while you right-click will cause you to start a new line or polygon. Holding down the Ctrl key while you right-click will cause you to start a new sub-line or sub-polygon.

How do I print?

You can print the contents of the screen at any time by clicking on File->Print to... and then choosing the device or file format you want to print to.

How do I associate a met mast or wind frequency table with a wind resource grid?

Whenever a WRG is asked for information regarding the wind resource at a point, it checks to see if it has a wind frequency table associated with it. It does this by asking its children and grandchildren in turn for the wind frequency table information. If it finds a wind frequency table it will use it but it will only use the first one it finds. So the way to associate a wind frequency table or met mast with a WRG is to make the wind frequency table a child or grandchild (etc.) of the WRG. You can do this by dragging and dropping the met mast layer on the WRG layer. Don't forget to load a single point WRG by going into the met mast layer's properties and pressing the Load Point WRG button.

How do I limit turbines to specific areas?

Please work through the tutorial. Its too long to explain in an FAQ.

How do I load a background image?

Click on File->Open Image and browse to the image you want to use. openWind can import images in common formats (TIF, BMP, JPG, PNG). When you load a TIF, openWind automatically looks for a TIFW file and if successful it takes the coordinates from there. Otherwise, it asks you for the coordinates of the four edges of the image. openWind is not a GIS. You are expected to have access to a GIS as well as the expertise to use it.

How do I load Vector Data?

openWind currently supports ESRI shape files but can be quickly and easily adapted to support other vector formats. Let us know what you want and we will think about it. Better yet, offer to code the import/export functions yourself and we'll be your friend and help you.

How do I load Raster Data?

openWind makes the somewhat arbitrary distinction between images that are merely decorative or do not contain an obvious grid of data values (we call these images) and rasters which we think of as being grids of values. From now on and throughout this website and the openWind software we will talk as if you accept this distinction.
openWind contains functions to convert images into rasters. However, if you want to import gridded data into openWind , it is best to use one of the following formats: ESRI ASCII grid (*.ASC); Surfer ASCII grid (*.GRD); WindFarmer digital terrain model (*.DTM); ESRI floating point grid (*.ADF); Binary interleaved data (*.BIL); Geotiff (*.TIF); Idrisi grid (*.RST).

How do I load a Wind Resource Grid?

Use File->Open Wind Resource Grid and browse to the WRG you want to load. At present we only support WAsP format WRGs but we're looking at improving this and we're open to suggestions.

How do I load a Wind Frequency Table?

Use File->Open Wind Frequency Table and browse to the WAsP TAB file you want to load. You will need to edit the properties of this layer to add the single point WRG. We refer to these layers interchangeably as "met masts" and "wind frequency tables".

What coordinate systems does OpenWIND support?

We really want to stress that openWind is not a GIS. It may look like one but there are several important distinctions. The first is that openWind does not project on the fly. The second is that openWind only works in meter grids as this is important to facilitate small-scale physical models. openWind will convert from Geographic (lat/lon) coordinates to UTM coordinates when importing data. From this point of view, openWind , at present, only supports standard UTM zones. However, if you have all your data in another single, consistent, meter grid projection, you can use openWind . You can also tell us the projection you are using along with its conversion parameters and we will consider making them a part of openWind .
Once you specify a UTM zone then that is the zone we will use for any future conversions. If you do not specify a UTM zone, openWind will set it based on the first set of geographic coordinates it encounters. If you choose to change the UTM zone within a workbook, openWind will not re-project the data already in the workbook. Conversions are carried out once when the data is imported. We do not project on the fly.
openWind only supports WGS 84 world datum at present although we may add others at users' requests. openWind is unlikely to ever support datum conversion. We prefer that you do this using your GIS of choice and leave us out of it.

How do I know openWind is giving me the right answers?

Please download the validation and theory document.

How do I export a layer?

Simply right-click on the layer you want to export and then select export. You will be prompted for a file name. You can select the file format to export to using the drop down list at the bottom of the Save File dialog. For instance, in order to save a turbine layout to Google Earth you right click on your site layout then choose export and then choose Google Earth KML as the export type. This will create a Google Earth compatible KML file which references turbine models on this server and can be used to create an animated simulation of a wind farm.

Why are the dialogs so small?

Because they can be. Almost all the dialogs can be resized so what you see by default is the minimum size of each dialog. Grab the bottom right corner and drag to get a bigger window.

How does the optimiser work?

The optimiser first checks whether the current layout is legal (i.e. that all turbines obey all the current constraints and have appropriate wind resource information) and if not, it attempts to find random positions for the turbines. If this fails, it attempts to pack the turbines.

Once a starting legal layout is available, the optimiser does a full test of the layout to get the starting energy. It then tests the layout again to get its first optimising benchmark. It then begins to optimise the layout.

Each iteration of the optimiser consists of the following steps:

1. the optimiser attempts to find a new legal position for each turbine. If the turbine made a good move last iteration, it will attempt the same direction this time (this momentum allows turbines to climb hills more effectively). Otherwise, it finds a new random perturbation. It does this by adding a gaussianly distributed random perturbation to the turbines x and y coordinates. If the new position is not a legal position or it obstructs another turbine's perturbed or fallback position, then a new random perturbation is made and so on until all the turbines have new legal positions.
   
2. the optimiser then runs an energy capture (which includes wake effects of course) and if the total energy is greater than the benchmark energy, it accepts the entire new layout (this tends to only happen at the beginning of the optimisation process) and the perturbed positions become the permanent positions and the new energy becomes the benchmark energy and we return to step 1.
   
3. if the new layout was not accepted as a whole, the optimiser looks at each turbine in turn and if that turbine got less than its benchmark energy, the perturbation is discarded and the turbine is returned to its permanent position and benchmark energy.
4. the optimiser then sums the total energy from all the turbines and if it is equal or greater than the benchmark energy, it runs another energy capture to see if it really constitutes an improvement. If not then we discard all the perturbations and return to step 1. If so then we accept all these new positions and energies as the benchmark energies and return to step 1.

Now a recent addition is to go through steps 3 and 4 again (hence the third set of lines in red sometimes). Attempts are ongoing to address the weaknesses of this method.

 

How do I make a wind map in openWind?

1.  right-click in the left hand pane (the tree view) and choose "new layer" then "windMap"
   
2.  drop an elevation raster onto the windmap layer (make sure you have it marked as elevation in the raster properties)
   
3.  drop one or more TAB files onto the windmap layer
   
4.  drop a roughness raster onto the windmap if you have one
5.  drop a vegetation height raster or polygon layer onto the windmap if you have one and want to use displacement heights.
6.  right-click on the windmap layer and choose "calculate"
7.  you will notice that the cursor has changed - use it to drag a box from top left to bottom right describing the area you want as your new windmap.
8.  choose the parameters for your windmap including how many and which output heights and press ok
9.  sit back and wait - I will multi-thread this calculation but its not done yet.