Windographer FAQ Technical


Windographer FAQs:

Data and File Formats

Exporting Data

Wind Turbine Output

Wind Data Calculations and Corrections

Wind Shear Analysis

Other Technical Questions

Troubleshooting (error messages)

 

Data and File Formats

What data format does it read?

Windographer reads almost every file type. It reads Met Tower, SoDAR, LiDAR, RWD, RLD, Nomad, Ammonit, Kintech, Campbell Scientific, Triton, AQSystem, ZephIR, Windcube and Pentalum. It interprets files automatically, detecting date format, time step, data type, measurement height, and so on. If it has trouble opening your data file, let us know so we can investigate. (We treat all customer data as confidential).

Can it read RWD files?

Yes, Windographer can read RWD files provided you have the SDR software installed on your computer. Windographer can also read NSD files directly. Windographer will store the scale, offset and serial number, which can be viewed and modified in the Calibration window.

Can it read NDF files?

Yes. Windographer can open NDF files written by the Nomad2 data logger by Second Wind Inc. Windographer will store the scale and offset information, which can be viewed and modified in the Calibration window.

Can it read SoDAR and LiDAR data?

Yes, it works nicely with data from ASC, AQSystems and Triton SoDARs, as well as ZephIR, Windcube, and Pentalum LiDARs. Please contact us if you have trouble opening any data file.

Can it read high frequency data?

No, the minimum time step it can accept is one minute.

Can Windographer read multiple data files into a single data set?

Yes, you can use File > Append or Append Folder to append many data files to an existing data set.

How much data can it handle?

There is no hard limit, as it depends on the computer capacity and the characteristics of the data. Above about 15 million data points (rows * columns) processing will probably slow down. We hope to implement improved memory management techniques to allow Windographer to handle larger data sets in the future.

Does Windographer provide wind data?

Yes, it allows free download of MERRA and MERRA-2 data, which is often suitable for long-term reference data.

Exporting Data

Does Windographer let me export graphs for my reports?

Yes, you can right click on any graph or wind rose to copy it to the clipboard or export it to a .PNG or .EMF file.

Does it let me export data?

Yes, the Export Data window lets you export some or all of the data set, and it lets you change the time step so you can export hourly averages, for example.

Can I control the export format of my data?

Yes, you can specify the date and time format, and you can specify any text string to indicate missing data.

Can Windographer export to WAsP, Openwind, Meteodyn WT, WindSim, or WindPRO?

Yes, Windographer exports TAB files and formats specific to Openwind, Meteodyn WT, and WindSim. Windographer supports multi-height exports to Openwind.

Can I remove the Windographer kite watermark from my graphs?

With a Professional or Enterprise Edition license, you can remove the watermark. The control for this setting is in the Tools > Options window.

Wind Turbine Output

Does Windographer calculate the output of wind turbines?

Yes, it can calculate the power output of an individual wind turbine in each time step, and compare the output of different wind turbines.

Does it contain a library of wind turbines?

Yes, the library currently contains about 200 wind turbine models.

Does it account for the effect of air density on wind turbine power output?

Yes, in each time step it calculates the air density and adjusts the power curve accordingly, using the standard IEC approach.

Does it account for the effect of hub height on wind turbine power output?

You can use Windographer to extrapolate to hub height for use in this calculation.

The calculated turbine output is not what I expected. What could be wrong?

Three factors affect the turbine output calculations:  the wind speed, the turbine power curve, and the air density.  Air density is most likely to cause unexpected results.  Check the air density by viewing it in the Time Series window.  Confirm that measured temperature and pressure have the correct units. 

Wind Data Calculations and Corrections

Does Windographer calculate wind flow over terrain?

No, Windographer is not a wind flow model. It analyzes time series data and lets you prepare that data for input into a wind flow model.

Can it correct for an error in the offset of a wind vane?

Yes, the Calibration window ( or the Apply Slope and Offset window) allows you to adjust the offset and/or slope of any data column.

Does Windographer take vertical wind speed into account?

Yes. The user can identify vertical wind speed data and then use the Inflow Angle Analysis window to analyze the vertical wind speed or calculated inflow angle. Graphs and tables show these factors vs direction, wind speed, month and hour of day.

Wind Shear Analysis

Why does the Monthly Statistics table for the wind shear parameter show different numbers than the Wind Shear Analysis window?

You can calculate mean wind shear in two different ways. If your data set covers 1000 time steps, for example, you could find the best-fit wind shear parameter in each time step, and then average those 1000 values. Alternatively, you could calculate the mean wind speed at each height, and then do a single curve fit on that mean wind shear profile. In other words, you could do the curve fit 1000 times and average the results, or average the wind speeds and do the curve fit only once.

In the Wind Shear Analysis window, Windographer uses the second method because we think it is more accurate. But if you create the Monthly or Annual statistics table for the power law exponent or the surface roughness, you are using the first method. We recommend that you refer to the Wind Shear Analysis window for any wind shear calculations.

Does Windographer use all wind speed sensors when it calculates the wind shear?

Yes, although you can choose to use a subset of all sensors in the Wind Shear Analysis window. You can also create a Calculated data column of a wind shear parameter and specify which sensors should be included.

Why do the mean wind speeds in the vertical wind shear profile not match the overall mean wind speeds?

When calculating the vertical wind shear profile, Windographer considers only those time steps in which all wind speed sensors contain data. This ‘concurrency’ requirement does not apply to the overall mean wind speeds.

Other Technical Questions

Can I run Windographer on my Mac?

Windographer runs on Windows, so to use it on a Mac you will have to run Boot Camp, Wine, or a virtualization application like Parallels, VMWare Fusion, or VirtualBox.

Can Windographer compare two datasets, or use data from a second source to predict the wind at a primary site?

Yes, with Windographer Professional or Enterprise edition, Windographer includes a Compare Data Set window for multiple data sets and a Measure-Correlate-Predict module.  The MCP window allows you to use a reference data set to extend a target data set.

Can I make a customized report from Windographer?

Windographer comes with four preformatted reports. We can create customized reports for a fee. And you can always create your own reports by exporting graphs and tables into a word processor.

Can I take a Windographer training course?

Please watch the training videos on our website for an overview of the software. We don’t have any scheduled training, although we can provide training in person, or over the internet. In most cases, an hour on the phone or a few email responses are all someone needs to get started with Windographer.

How do I share my favourite flags and flag rules?

You can create a windog file that contains the flags and flag rules that you want to share. When another user opens that windog file, they can add those flags and flag rules to their existing favorites.

Windographer stores a small file for each favorite flag and favorite flag rule which you can copy and share. The location of these files is controlled from Tools > Options > Folders. Note that if you replace your favorite flag files, you will lose any previous favorites that you had.

Why is there one direction sector missing from my wind rose?

When creating a wind rose, Windographer considers only those time steps in which the wind speed exceeds the ‘calm threshold’ that you enter in the Configure Data Set window. When creating a wind rose for a particular wind vane, Windographer will choose to query data in the wind speed sensor nearest in height to the wind vane.

This behavior often happens after you have flagged your wind speed data for tower shading. For example, if you flag Speed 60mA as Tower Shading whenever the direction is between 40deg and 70deg, and then look at the wind frequency rose for the 60m direction, Windographer show no data in the 40deg to 70deg sectors.  The wind rose will include only those time steps that contain valid data in both the 60m direction data column and the Speed 60m A data column, so all the data between 40deg and 70deg is flagged and will not be included in the wind rose calculations by default.  You can choose to include that that data by checking the Tower Shading flag box in the Filter section.

How do I calculate hub height turbulence?

When you use the Vertical Extrapolation window to extrapolate to hub height, Windographer also extrapolates standard deviation if possible.

Troubleshooting (error messages)

I got an error that Windographer can’t find the help file.

Windographer is looking for the windographer.chm file in the same folder as the Windographer executable folder. The two files have to be in the same folder and have the same name. So if you rename or more the Windographer executable , you will have to rename or more the windographer.chm file as well.

When I try to append my file Windographer tells me “Windographer cannot append this data set because it is out of phase with the master data set.” What does this mean?

Windographer requires the time stamp patterns to match in order to append data. If the original file contains 10 minute data, the appended data must be 10 minute data with matching minutes. For example, a file with time stamps of 1:15, 1:25, and 1:35 cannot be appended to a file with time stamps of 10:50, 11:00, and 11:10. You can use the Apply Time Shift feature to adjust the time steps in a given file.