Stadimeter range is off (Bug?)

[PeriscopeDepth]

In the mods section, there is a mod that fixes three IJN ship's mast height that might have resulted in bad ranging.

PD

[NefariousKoel]

Originally Posted by PeriscopeDepth

In the mods section, there is a mod that fixes three IJN ship's mast height that might have resulted in bad ranging.

PD

I have tried the mod and had the same problems.

I'm also running at 1280x1024. Perhaps the 5:4 ratio is screwy with it. I've been playing with map contacts on also to check my range estimate. On smaller vessels I don't have to drag the image down the mast as far as a taller one it seems.

[nattydread]

I suspect the stadimeter is inaccurate at range by dev design in part. The detail on ships atrange is reduced enough to make accurate distance claculatioons difficult, espeically considering the limited fidelity/resolution in the adjustment of the stadimeter. Basically at range the masts arent rendered very well. It makes range calculations very loose until the ship is close and fully rendered in higher detail with masts accuratly rendered and the stadimeter's limited fidelity/resolution of no consequence.

[Krupp]

Originally Posted by nattydread

I suspect the stadimeter is inaccurate at range by dev design in part. The detail on ships atrange is reduced enough to make accurate distance claculatioons difficult, espeically considering the limited fidelity/resolution in the adjustment of the stadimeter. Basically at range the masts arent rendered very well. It makes range calculations very loose until the ship is close and fully rendered in higher detail with masts accuratly rendered and the stadimeter's limited fidelity/resolution of no consequence.

I find hard to believe that the dev's have made the range measuring work so that some ships wouldn't use the mast top (OR, mast at all) as a measuring point due the poor rendering, while other ships would use. Their masts are equally visible to those that had biggest error in the ship height.

Example carrier Taiyo was one of two carriers that didn't take the mast top as a measuring point, but the flight deck instead (odd, cos the mast is clearly visible to a long distance). But when you measured the distance to her, using the stadimeter same way as with any other ship (to mast top) you got the distance of 340 meters when the ship actually was at 1000 meter range. That would make your shot miss the crosshair.

Reason for this was that in the ships cfg-file, ships height was only around 16 meters or so. That clearly can't be the case (when talking about 17,000 ton carrier), because the actual height (with the mast) is 43.5 meters.

I've corrected all the japanese (ships you'd attack) ships cfg-files so, that the ship data, most importantly, the heights would match the dimensions they suppose to be. Not all ships had bad data. Few big errors, some medium and small errors. What ever the case, I corrected all heights and other dimensions, some speeds and masses too. AND, all the fixed data comes from the developers, not from my head.

I just tested with the stadimeter(again, but first time in patch 1.2) all the jap merchants for their heights/ranges. They were ok (i.e. patched 1.2 are still porked, but the JP Ship Dimension Fix 1.2 corrects them). Variation in 1000 meters was +-30meters. NOT nearly 650 meters as before (in worst cases)! I use 1440x900 resolution.

I'll test the japanese warships later today. But I'd quess that they are ok too, because there weren't any changes in the merchants. But well see that later.

[FinnN]

Originally Posted by Krupp

Example carrier Taiyo was one of two carriers that didn't take the mast top as a measuring point, but the flight deck instead (odd, cos the mast is clearly visible to a long distance). But when you measured the distance to her, using the stadimeter same way as with any other ship (to mast top) you got the distance of 340 meters when the ship actually was at 1000 meter range. That would make your shot miss the crosshair.

Whilst this doesn't apply to the game, if you look at various photos of the Japanese carriers you'll see that they could 'flatten' the masts by rotating them outwards pointing away from the ship so that when aircraft were operating from the carrier there would be a minimum of obstructions. This means that the height of the flight deck would be the most reliable way of measuring the range of carriers. Possibly this is where the different spotting locations are coming from. In any case, in game terms, as you can't spot an arbitary point on a ship to get the height/range it should be consistent - or point out clearly when and why it isn't.

Have fun
Finn

[Krupp]

Originally Posted by FinnN

This means that the height of the flight deck would be the most reliable way of measuring the range of carriers. Possibly this is where the different spotting locations are coming from.

If so, why didn't they do so for every carrier in the game? And if intentional, why there is wrong measures in every dimension for some ships, lenghts, widths etc? They have nothing to do with the firing data. Some lenghts are way of. Also, why the dev's say in the manual: "...you need to have the waterline, as viewed in the second picture, touch the masthead of the first one."

[akdavis]

Originally Posted by nattydread

I suspect the stadimeter is inaccurate at range by dev design in part. The detail on ships atrange is reduced enough to make accurate distance claculatioons difficult, espeically considering the limited fidelity/resolution in the adjustment of the stadimeter. Basically at range the masts arent rendered very well. It makes range calculations very loose until the ship is close and fully rendered in higher detail with masts accuratly rendered and the stadimeter's limited fidelity/resolution of no consequence.

No, I don't think that is the intent. If the correct mast height is used and conditions allow for a precise reading of angle, there is no reason there should be error in the returned range. That would be like introducing a math equation that only works sometimes. Furthermore, a system in which you have the same error at close range as at long range makes no sense. The limited resolution of the screen and tool when rangeing on distant targets already introduces a great deal of error.

If they wished to introduce rangeing errors, there would be more logical ways to do so.

[MudMarine]

Shippers,

I think the devs purposely place error in the stadimeter. Even then in 1950 rnage was off plus or minus 35 yards. I think the devs used this manual for thier model.
Also you will find other factors. Funnel smoke obscuring the mast, intentionly heighten or shorten by the enemy, camoflaged or the water line obscured at long range by the horizen.

I believe the devs got it right. If they used the manual I have posted a link to has been used aas a reference. So given the info in the manual the devs have designed in a fudge factor in the stadimeter to reflect what they got from this manual.

Submarine Torpedo Fire Control Manual
http://www.hnsa.org/doc/attack/index.htm


Exerpt from: Submarine Torpedo Fire Control Manual Cia 1950:



(e) Of the three methods the radar ranges are the most accurate and depend primarily upon the adjustment of the radar which is usually plus or minus 35 yards. The accuracy of telemeter or stadimeter

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ranges depend first, upon the skill of the observer and second, upon the accuracy of the estimate of target masthead height.

(f) The value of the masthead height of the target may be obtained by intelligence, estimate, or by a method referred to as "radar stadimeter" (telemeter) estimate. The latter of course is the most accurate and is accomplished as follows; assuming that the target has been tracked using the ST periscope, the Type II periscope is raised immediately following an ST periscope observation, a stadimeter range observation is made as described above, but instead of reading range on the scale, the masthead height is read opposite the value of the TDC generated range.
(g) When radar ranges cannot be obtained the Approach Officer must rely upon his ability to correctly estimate the height of the funnel or masthead, or other prominent mark on the ship's structure above the water line. If the target ship can be properly identified an accurate value may be obtained from intelligence information supplied the ship. If this is not available the following procedure will he of assistance:


(1) Count or estimate the number of decks that are seen above the main deck.

(2) Add to this figure the approximate number of deck heights equal to the observed freeboard.

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(3) Multiply the total by eight to determine the height of the top of the bridge structure above the visible waterline.


(4) Using height of bridge structure above the visible waterline as a yardstick, approximate the masthead height. The masthead heights of merchant ships are on the average about 2.1 times the bridge height (above waterline). A masthead height which appears to be shorter than normal will be about 1.7 to 1.8 times the bridge height, while one which appears to be higher than normal is approximately 2.2 to 23 times the bridge height.

(5) Funnel heights may be estimated by approximating the number of deck heights of the funnel which is seen above the top of the bridge structure and adding this height to the bridge structure height.
(6) At extreme ranges it must be remembered that the waterline is below the horizon. This necessitates estimating the position of the waterline.

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(h) The following points should be kept in mind in height determination:
(1) Masthead heights may be purposely altered by the enemy to cause inaccuracies in periscope ranges.


(2) Tops of masts may be camouflaged in such a manner as to be invisible under average visibility conditions at any except short ranges.

(3) Funnel height is normally sufficient to insure that the smoke which is blown in the direction of the bridge by a tail wind will pass well over the bridge.

(4) Coal burners require taller funnels to insure adequate draft.

(5) Funnels of modern vessels having forced draft do not require as tall a funnel as older vessels without forced draft.
(6) Diesel propelled ships require no draft. Funnels are normally short, are not required, and generally have such dimensions as to provide a good appearance on the ship.



Regardless of the methods employed by the individual Approach Officer, skill in estimating masthead heights, and ability to obtain accurate ranges can

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be acquired and maintain only by constant practice. Even when radar ranges are available daring an approach the Approach Officer should also obtain telemeter ranges as a means of improving and maintaining his skill.

With that said the Devs may have just ot it right. I would not complain about this feature. The target book in meters instead of imperial on purpose? I think so.

So for those realism buffs think about it. This exerpt explains a lot.