How to: Weather Maps Creation with ZyGRIB and Weather Commander

[ph34rb0t]

I’ve been messing with weather maps a bit. The process is basically pretty straightforward and scales with the amount of detail you want in the weather map.
Weather maps are discussed in BMS-manual, chapters 5.7 to 5.9.

Until there are more sophisticated tools available that automatically fetch and convert GRIB data into BMS’ FMAP format, we have to do everything by hand. The process is not complicated, but requires a bit of work and planning.

Here’s a small(?) how-to without illustrations.

1. Prerequisites

1. Download Weather Commander from http://www.weapondeliveryplanner.nl/download/index.html
2. Download ZyGRIB from http://www.zygrib.org/#section_windows (pick the download with high resolution maps!)
3. Extract both tools from the zip file, then run Weather Commander.exe to see if it runs, then open ZyGRIB.exe to do the same. If both tools open, fine.

2. Getting Data

First of all, it is necessary to fetch the current weather data in ZyGRIB. On the world map zoom (mouse wheel) and drag (keep the middle mouse button pressed and drag) until you have an area in view that roughly corresponds to the BMS theater.
Click and hold the left mouse button in the map to do an area selection for which you want to download the weather. Again, stick to an area that roughly corresponds to the theater. If you’ve got a good selection go to “File” -> “Download GRIB” (or press CTRL+D).
Configure the data package. The more options you select, the bigger the download will be. “Interval” determines the hourly interval between weather snapshots. “Period” determines the amount of days for which data should be downloaded. If you only want weather for a Tactical Engagement, “3” and “1” are the obvious respective choices for interval and period. For campaigns in real weather, you might want to download data for 3 or 6 hour intervals across 10 days. Leave all the other checkboxes as they are.
Once you’re done, click “Download” and wait. A window will pop up and ask you about the location in which the weather data should be saved. The default location, “ZyGRIB\grib” in “C:\Users[Username]” is totally fine, so click “Save”.
ZyGRIB will automatically process the saved data and superimpose it on the map.

3. Transferring data into Weather Commander

Once ZyGRIB has loaded the weather and displays it on the map, you can mess about a bit with it. In the toolbar, click the rocket icon (or press CTRL+A) to create one of those animations you usually see on the news. Once the animation was loaded, you can control it with the button and slider at the bottom. The animation feature is useful if you want to create reality-based FMAPs for a certain period of time and need an animation to have users see what kind of weather is included. The data shown in animation window adheres to the display options selected for the map, so you can create different animations for cloud cover, temperature, etc. A weather map animation is also useful for determining the direction and speed of the weather map movement in BMS.

You can also switch between different weather snapshots with the slider at the bottom of the main window.

The data you need from ZyGRIB for painting a weather map for BMS is:

• Cloud cover
• Air pressure
• Air temperature
• Wind direction and speed

ZyGRIB’s “Weather Map” menu offers a fair amount of options of what should be displayed in the map. It is advised to concentrate on a single parameter at a time.
You might want to have Weather Commander open by now. Create a new map in it with “File -> New” and name it according to the weather snapshot you’re painting. Something like “KTO_20151110_0600”. Or pick a filename that is compliant with the “auto update” function for the weather map in BMS (see chapter 5.9 in BMS-Manual) if you want to do continuous campaign weather maps.

In ZyGRIB, select “Cloud Cover” from the “Weather Map” menu and you’ll be presented with the cloud cover over your theatre. On the left side of ZyGRIB’s window, there’s a readout for weather data at the position of the mouse cursor on the map. Look for the “cloud cover” parameter and move your cursor around the map. The value will change as you move your map cursor in and out of cloud coverage.
Before you start painting your cloud coverage map in Weather Commander’s “Weather Type” mode, make a call regarding tresholds between modes. A cloud cover value of 10% and lower can still be described as “sunny” in WC, while “fair” might range from 10-40% coverage. The trickiest part is determining when conditions are “poor” or “inclement”. Look at the “relative humidity” map mode (“Weather Map” menu) or enable the precipation display mode (“Weather Map” -> “Precipation”) to see areas where inclement weather is most likely.
Once you have a general idea about the current cloud cover status for your theatre, paint it in Weather Commander. The process is outlined in BMS-Manual, page 5-60ff. The best way to paint cloud coverage is starting with the type of coverage that encompasses the most part of the map, e.g. “fair” and then add spots of poor and inclement weather that roughly correspond to the ones on the weather map in ZyGRIB. Vary brush sizes in WC to paint larger or smaller pockets and to break up potential straight lines of cloud covering cells. It is helpful to use Window’s 50-50 window split functionality. Select WC’s window and drag it to the left edge of the screen, then select ZyGRIB’s window and drag it to the right side. Each window will now take up 50% of screen space.

After you’ve painted your cloud coverage pockets, save the FMAP file in WC, then select the “Pressure” tab to transfer the ambient air pressure to the weather map. Switch ZyGRIB into “Temperature” mode from the “Weather Map” menu as temperature is a reltively good indicator for air pressure and because the color gradients are better contrasting with the air pressure readouts. You should see some curved lines all across the map. These are isobars, i.e. lines of a constant ambient air pressure. The display of these lines is controlled from the “Isolines” menu. Clicking "Isobars (MSL) in the “Isolines” menu will toggle the lines on the map. “Isobars Spacing” controls the amount of lines displayed. You might want to set this value to “1” to produce a more accurate picture. Enabling “Isobars Labels” from the menu will display the pressure value (in hPa) on the corresponding line, which makes recreating those lines in WC somewhat easier.
The transfer of the air pressure values into WC depends on your desire for accuracy and is pretty straightforward. Pick a value for the air pressure from the slider and a brush size and then start painting. Keep in mind that air pressure can only be varied in intervals of 1 hPa in WC, but air pressure gradually rises or falls in between isobars. So either paint the entire area between a “1015” and “1016” isobar with a “1015” value in WC or rougly split the area 50-50 and paint one half with “1015” and one half with “1016”. Make sure that you don’t leave any cells unpainted as these might contain absurdly high or low air pressure values. Once you’re done painting, save the FMAP in WC and select the “Temperature” tab.

In ZyGRIB, make sure that you have “Temperature” mode selected from the “Weather Map” menu. Also enable the temperature readouts on the map with “Temperature (2m)” from the “Weather Map” menu (or by pressing CTRL+T). Switch off the isolines if you find them distracting. You will then be presented with temperature values for each cell on the map. Transferring these values into WC works just as for the ambient air pressure by selecting the temperature value and brush size and painting the desired area with it. Accuracy again depends on what you need in BMS. If you’re lazy, you can simply paint large areas with a rough mean temperature determined from the real weather map and then cover the boundary between these areas with a wide or narrow intermediate temperature zone to avoid rapid, huge temperature fluctuations when crossing from one area into another. Or go all out with a small brush and paint the map cell by cell. In any case, save the FMAP once you’re done and move on to the last and most annoying element - the wind (“Wind” tab in WC).

To obtain an overview about the wind situation, put ZyGRIB into wind mode by selecting “Wind” and “Wind Arrows” from the “Weather Map” menu. If you need an index for the colors on the map enable “Weather Map -> Options -> Show Color Scale” (or press CTRL+Y). The distribution of wind speeds is displayed on the map while the wind direction is indicted through the arrows. Numerical values for direction and speed can be obtained for the cursor position from the “Wind” fields in the “Weather Data” readout.
Transferring wind data from ZyGRIB into WC is a bit annoying as wind direction and speed tends to vary a lot over a large area. As usual, it’s up to you what to make of it. When painting large areas, keep in mind that you need to account for two factors this time - wind speed and direction. You should observe the areas between larger cells of constant wind direction and speed to smooth the transition, otherwise your ride from one cell into the next in BMS will be fairly rough. Once you’re done painting your wind map, save the FMAP in WC.

Congratulations, you’ve just finished your first weather map. Repeat the process as often as possible with other snapshots of real weather.

4. Auto-Change and Shifting

As of BMS 4.33 in Nov 2015, the “weather map” functionality allows for two methods for variation over time. The entire map can either be shifted into a certain direction (heading) with a certain speed (see BMS-Manual page 5-59) or be replaced with another map at a certain point of time (see BMS-Manual page 5-63). Weather Commander allows previewing the shift over time with its animation controls the readout on the right is the elapsed time since the shifting process has started, which is useful for estimating the weather conditions at a certain point in a campaign or TE.

The best results are obviously obtained with a combination of both methods, using ZyGRIBs animation mode to determine overall weather map shift and then changing out the entire weather map at a certain point in time for a new one that is closer to the real world conditions. For example, you create a weather map for camapign day 1 hour 0 from real world weather at, say, 0600. You then create another weather map for day 1 hour 6 from real world data at 1200. You do this for as many days as you think is necessary and then put them into a format that can be used by the auto update function. (The first map would have to be named be named 10000.fmap, the second 10600.fmap, the third 11200.fmap, the fourth 11800.fmap, etc…; see BMS-Manual.) In ZyGRIB, you’d then need to determine the rough movement direction and speed for most of the weather in the theatre. The best results are obtained by creating an animation in “Clouds” map mode because clouds often appear in solid fronts and provide an easy point of reference. Look how far a significant cloud front has traveled in the interval that you’ve created your weather maps for and then try to create that movement direction and distance with the animation controls in WC. Note the values for direction and speed in a text file and input them in BMS’ weather control.
Since the values for shifting weather maps are not dependant on which weather map is currently loaded, they should be changed at change time when the next weather map is loaded. Since this is not practical for campaign plays, especially in multiplayer, weather pattern observation should be done for a larger interval (a few days’ worth of weather data) to determine average movement direction and speed.

One thing to keep in mind when painting real weather data in Weather Commander that is to be used with map shifting are the map edges. As the map shifting mechanism in BMS loads values at the edge of the theatre map on its opposide end after they have left the theatre boundaries, it could be that there will be some very rough transitions after such a shift has taken place. To illustrate my point, create a weather map in WC with a poor weather cell in the bottom right corner of the map. Put a smaller inclement cell at the very corner of the map. Then set map movement to 135° at 30 knots and run the animation. Notice how the cell disappears at the bottom right and reappears at the top left - with a rough transition from sunny to inclement at its very edge in its direction of movement. This will also apply to temperature, pressure and wind data in these cells. Leave a map like this running in BMS for too long and you will suddenly run into a completely diffrent atmospheric environment. Not quite fun in my book.
To avoid this, ensure a smooth transition by painting the edges of your weather map with uniform conditions, even if it means sacrificing realism from the real weather data. That way, you can run each weather map for as long as you like in your campaign without anomalies.

I can’t think of anything more to add for now, but I hope you find this useful.
Feel free to discuss this or weather maps in general or share your maps here.

Attached to this post are two very rough maps depicting today’s real world weather for the KTO and the forecasted weather for the 17th. None of both is auto-update and shift compliant (see section 4 above) and might contain rather rough wind shifts, but they might be useful as a reference. If you want to test them in BMS, put them into Data\Campaign\Save and select them from the weather management menu.

I need a beer now.

There is now a tool to automate the GRIB -> FMAP conversion process!
https://www.benchmarksims.org/forum/showthread.php?24349-Release-Grb2fmap-GRIB-to-BMS-Converter

Quick question to the devs: Weather maps are shifted with campaign time, not 3D time, right?

[Khronik]

Are there any internal / public documents, and or info which go into detail about the FMAP format/structure?

[Mav-jp]

that is a hell of a post thank you for that.

moderator please make it sticky.

if your question is about map shifting when in UI. IIRC yes

[Arty]

thanx ph34rb0t

To have an almost 1-1 preview like weather commander:
From zygrib from Waether map Option disable all but show color scale and grib grid.
from Earth->map quality set scale to 1km
From Isolines have ISOBars MSL checked to see the pressure lines,
same you can do for temperature by selecting
Isolines->Isotherms->2m
Isolines->Isotherms spacing->2
check Isolines Isotherms labels

You can disable from earth and other labels like cities.
For temperature enable weather map->Temperature 2m (this shows the values on the squares)
Zoom at the level of weather commander
Now you have squares in zygrib like you see them in weather commander.

This makes it easier on painting more accurately.

Still is a pain process… needs to become quicker… maybe this will help tbuc that makes the app for it.

[ph34rb0t]

@Khronik:

Are there any internal / public documents, and or info which go into detail about the FMAP format/structure?

You need to ask the devs about that. I’ve tried to open a FMAP file with Notepad, but it isn’t human-readable.

@Mav-jp:

if your question is about map shifting when in UI. IIRC yes

Awesome! Should make campaign play much better.

@Arty:

From zygrib from Waether map Option disable all but show color scale and grib grid.
from Earth->map quality set scale to 1km
You can disable from earth and other labels like cities.
For temprature enable weather map->Temprature 2m (this shows the values on the squares)

I think these settings are the defaults for ZyGRIB. And unless you enable additional download options, you only end up with temperature values for an altitude of 2m.

[Arty]

@ph34rb0t:

I think these settings are the defaults for ZyGRIB. And unless you enable additional download options, you only end up with temperature values for an altitude of 2m.

They weren’t for me.

[ph34rb0t]

Hint: If you download the data with 2° resolution, you end up with a much simpler depiction of the current weather in the thetre. This might be especially useful for wind data.

Here are two generic weather maps. Number one was made from real world data (pressure gradient, temperature, wind) and is compliant with an east-west (90°) shift while number two is improvised and can be shifted in any direction.

• Edit:

Just a bit of feedback on one of the maps from above.
I’ve loaded map #2 as the weather map for the KTO and set wind direction to 315° and wind speed to 10 kts.
While I’ve flown a mission at 9 am in fair weather at the home base and at the target area and returned in sunny conditions, a mission around three hours later is briefed with sunny weather at home and poor weather at the target. So I assume that my maps work as they should.

@Arty:

They weren’t for me.

Hm. Weird.

[pandacat]

Still a little confused about the role that WC plays in the whole process. Correct me if I am wrong:
1. zygrib is used to acquire real world weather data
2. Once you obtain the data from zygrib, you use WC to fine-tune and modify the maps
3. You can also use raw converted data from zygrib directly if you don’t want to mess around with WC

Is this understanding correct?

[Jackal]

Dear pandacat,

according to what I have read and learned from all above, I think your understanding is all correct.

With best regards,