Virtual Skipper

[najevi]

I am trying to determine the most efficient way of displaying race courses at vsk.wikia.com Since there could easily be several hundred to a few thousand, it will not be very efficient or wise to simply upload JPG/PNG files. (Anyone who has installed the RC44 boat model will have discovered how the JPG image per Track.Gbx method of documenting a race course is terribly hungry on disk space.)

If you have a good understanding of the coordinates used by the VSK5 custom race editor (and presumably stored in the <track-name>.Gbx files) then please do your best to answer the following.


1. How big is the 3D-world map for each of the 16 sailing venues that come with VSK5? (The Sydney map is approx. 3200x2400 pixels at maximum zoom out and the zoom magnification seems to be 7-times so approx. 22400x16800 pixels at maximum zoom in.)
1a. Is this correct? [only for Sydney, different for others]
1b. Is it the same for all venues?) [No. Not all venues are the same size.]

2. (answered) Is there more than one map for each of the 16 sailing venues? (I've seen a few different Nordic and Tropical maps.)

14 of 16 seascapes are fixed/locked terrain. Nordic and Tropical seascapes are a blank canvas allowing user customization of terrain. Nordic and Tropical maps will therefore need to be uploaded to the wiki as needed using PNG or JPG images.

3. ( answered ) Are the maps from prior version of VSK re-usable on VSK5?
3a. Might this explain why I seem to see many different maps for the one venue?

• VSK4, 32AC and VSK5 maps can be used with the VSK5 client
• VSK3 maps might be usable
• The many different maps for the same venue is only for Nordic and Tropical venues - explained elsewhere

4. ( answered ) Regarding the block based map building that Maitai et al used to create the "map of the world" 3d-world map - is that widely used by other community members?

Used primarily for solo play however some clubs (notably Virtual-Winds) race multiplayer online with that world map regularly.

5. What coordinate system does the editor use? [simple square grid]
5a. Is it pixel based?
5c. Where is the origin? (Top left pixel is a common standard.) [near bottom left]
5d. Are negative coordinates ever used? [assume yes]
5e. Is the scale of px:Nm the same for each sailing venue? [No. Not all the same.]

6. (answered) Do you know how to extract the coordinates of each mark/buoy from the Track.Gbx file?

No. Only Nadeo can assist with dumping these coordinates to ASCII form.

Why do i ask?

I am trying to determine the most efficient way of displaying race courses at vsk.wikia.com. I like the idea of leveraging the Google Maps concept and have access to that extension. It involves tiling each 3D-word into 256x256 pixel tiles and dynamically selecting only those tiles needed to display a race course area. An overlay feature with simple polyline and icon style graphic capability is then used to display the marks and legs of a course in solid colors.

What I am not sure about is how to get my hands on a high-resolution map of each sailing venue ... showing the entire venue. (It appears that any of several file formats are suitable - including .dds) The 3D-world view includes perspective that cannot be reproduced in the Google maps model but I suspect it is still the more efficient approach to take.

If this subject interests you then please read the following wiki forum post and offer your feedback/advice. ( http://vsk.wikia.com/wiki/Forum:Is_there_a_Google_Maps_guru_reading_this%3F )

Regards,

[kiwi_bardy]

[najevi]

Thank you. I found more information in the Manual after being prompted by that thread. (I also found reference to the wind strength - something I recall having questions about in the past.)

Understanding that 14 of 16 seascapes/venues have fixed/locked terrain I am encouraged to pursue a tile-based approach for displaying courses at those venues leveraging the Google Maps API.

• Nordic and Tropical will have to be treated as the exception to the rule and require JPG/PNG/GIF uploads at a suitable resolution.

This plan still hinges on extracting coordinates for the racing course marks from the Track.Gbx file. So there are still a few more "miracles" needed.

If any user (or Nadeo) has pieced together a composite image of the entire map area for the 14 venues then please post some URLs for download.

[kiwi_bardy]

[najevi]

In case others are of the same misunderstanding as Bardy, I should clarify that the Google Maps API I am referring to is a generic set of tools that will accept any image as it's map. In the case of the 14 sailing venues that come with VSK5, the image(s) I plan to use are a full resolution image of the Nadeo generated map for each of those 14 locations. For examples of this having been done for another online game wiki refer to the wiki forum post mentioned above and follow the links provided there.

The coordinates of buoys contained in the Track.Gbx file (and hopefully to be dumped in ASCII readable form in either a Result.csv file or similar) will therefore be easily applied to such a map and should yield an identical chart of the course minus any water and air traffic that the track designer may have programmed. (I may suffer a few headaches over the algorithm for drawing a correct path through gates. Even the Nadeo generated path sometimes fail to correctly illustrate when a gate buoy must be rounded. I am not sure that I know the precise rules for this but somebody does.)

That is why I am asking for sources of the Nadeo created maps. With enough time and patience those could be generated manually however I have to believe that these images are sitting on a disk somewhere on the planet just waiting to be emailed or downloaded.

ETA sometime in October depending on how much help I get from someone experienced with the API.

I do plan on using the real world maps/satellite images/etc. of traditional Google maps at each Venue page just to show where in the real world each seascape can be found. However that is intended more as a piece of trivia or curio for the geography buffs and world travelers. It is independent of the display of racing course data. Setting this up should take less than a week. ETA sometime in September.

So you see the real world maps will not come into play with respect to displaying race courses but will come into play when illustrating each Venue page. FYI I did some google research to come up with the following list of lat/long data for each of the venues but I'd appreciate someone else checking that these are accurate. http://vsk.wikia.com/wiki/Category:Venues
A few of the venues had multiple same named places so a little sleuthing was necessary. Feel free to make any corrections necessary.

[kiwi_bardy]

Ahhhhhh - realisation dawns.

;o)

[admiral]

[maitai]

I ahve search a lot on that quation when doing the worldmap. Although I made a few discoveries, I don't think it's enough to extract reliably mark coordinates. I am afraid we have to wait for Nadeo help on that one.
_________________
www.virtual-winds.com

[admiral]

Obviously what is needed is all map coordinates expressed in Longitude and Latitude. It's up to Nadeo to implement. An Easy way out could be to just have latitude and longitude for the north-west corner of every venue, All else can then be derived from the grid size.. transfer length and with in hundreths or thousends of degrees.

When the grid is small enough projection errors, a flat area in vsk vs a spherical part of the globe, should be neglectable.

AFAIK all vectors (Currents, Winds) are allready in ° and Kts or m/s


basic venue 20 x 20 miles = 0.333° x 0.333° at the equator

[admiral]

neglecting projection errors may not be that smart:

http://en.wikipedia.org/wiki/Geographic_coordinate_system

Copy and Paste for the lazy:
On a spherical surface at sea level, one latitudinal second measures 30.82 metres and one latitudinal minute 1849 metres, and one latitudinal degree is 110.9 kilometres. The circles of longitude, meridians, meet at the geographical poles, with the west-east width of a second being dependent on the latitude. On the equator at sea level, one longitudinal second measures 30.92 metres, a longitudinal minute 1855 metres, and a longitudinal degree 111.3 kilometres. At 30° a longitudinal second is 26.76 metres, at Greenwich (51° 28' 38" N) is 19.22 metres, and at 60° it is 15.42 metres.

The width of one longitudinal degree on latitude \scriptstyle{\phi}\,\! can be calculated (to get the width per minute and second, divide by 60 and 3600, respectively) where Earth's average meridional radius approximately equals 6,367,449 m. Due to the average radius value used, this formula is of course not precise. You can get a better approximation of a longitudinal degree at latitude by:
where Earth's equatorial and polar radii, 6,378,137 m, 6,356,752.3 m, respectively.

Length equivalent at selected latitudes in km
Latitude Town Degree Minute Second ±0.0001°
60° Saint Petersburg 55.65 km 0.927 km 15.42m 5.56m
51° 28' 38" N Greenwich 69.29 km 1.155 km 19.24m 6.93m
45° Bordeaux 78.7 km 1.31 km 21.86m 7.87m
30° New Orleans 96.39 km 1.61 km 26.77m 9.63m
0° Quito 111.3 km 1.855 km 30.92m 11.13m

I do think that latitude conversions can be the same for any venue however the venues shoudn't be to large. (This will never work for a world map..)Though to get an average maybe the middle point is better then the north-west corner as i suggested in the earlier post.

Frankly maybe some who know the venues well are able to determine latitude and longitude for each venue?

[najevi]

Maitai - when you say that you could not figure out the mark coordinates from the Track.Gbx file then I definitely sit up and pay attention. It would be ideal if Nadeo was to provide these coordinates (along with other track data) in ASCII form along with each Track.Gbx file. Admiral and Bardy are both aware of my wish list in that regard.

Just to clarify my intention with this set of questions. At this time, I have no interest in plotting race courses on a map of the real world. My interest extends only to plotting marks to overlay on a map of each of the Nadeo provided venues/seascapes.

This means that latitude and longitude measured in degrees and minutes are not required. Spherical coordinates are not required. Simple square grid, pixel based coordinates of each mark on the course are all that is necessary.

Maitai, thanks for your other answers via PM.

The only remaining question of immediate interest is where can I obtain high resolution images of each of the venues/seascapes? I suspect Hylis et al will need to come to the rescue on this point.

[maitai]

What I meant is I was able to identify one single bouey coordinates, by comparing binarily 2 gbx with only a small move of a single bouey. That allowed me to figure out the coordinates system at that time, but I am not sure I remember what it was (I think 0,0 is just the left/down corner of the grid, but I am not sure and too lazy to do it again). The problem was to identify the other marks because they can be anywhere in the gbx file, there is not structure as such, it's just a collection of objects in whatever order as I can tell. And you don't even know how many marks you are looking for....

To make a long story short, without Nadeo's help it's hopeless I think, or it will take a huge effort to "crack" it for a somehow small reward.

PS: this knowlegde would also probably allow to inject one player's replay track in another replay based on the same map, allowing for ghost replay. And to calculate some stats (distance and therefore average speed on water, number of tacks, etc). A very useful thing when playing "time-record" course type in solo mode. But again Nadeo's help is necessary here too.
_________________
www.virtual-winds.com

[admiral]

[najevi]

[admiral]

How much can you get on a screen with the free camera at the highest point?

If it only takes like 4 screenshots at like 1900 x 1200 that need to be pasted that may proof faster... then somebody tweaking that camera hight to get a high-res shot of the whole venue.