Content archived here are formula that once being used for Line of Sight calculation but currently deprecated and replaced by other formulas. Please visit the main Line of Sight page for further detail.
Effective Line of Sight (25 old formula) Edit
 Effective LoS = Recon LoS×2 ＋ Radar LoS ＋ √(Fleet total LoS  Recon LoS  Radar LoS). This is the formula used since Spring 2014 event; in 25, 35 boss node, and any node with the seaplanesearching animation.
 Due to the formula, recon planes will contribute more to effective LoS than radars. For the purposes of fulfilling effective LoS, avoid using radars that do not give at least +10 LoS.
 You can make an exception to the above if your ships require other equipment for more damage, in which case you can make a DD/Yuubari a radar 'mule' to contribute to LoS by stacking radars.

ONLY Recon planes' (yellow & seaplanes) LoS values are doubled. LoS from carrierbased bomber planes (red & blue) are not doubled, but in fact square rooted. Avoid doubling dive bomber and torpedo bomber LoS values when calculating LoS.[It is currently uncertain whether LOS from bombers contribute to Recon LOS (x2) or Fleet LOS (sqrt). Testing required.]  You know you fulfilled the LoS requirement if you see a short animation with a seaplane flying to the node and back to your ship icon, plus the flagship's image appearing onscreen. Otherwise, you will be diverted offcourse to a dead end without the animation playing.
5:065:11 of this video here shows what the animation looks like: http://www.youtube.com/watch?v=Jx1tNuCeSE
 You can have a high total LoS and still fail the effective LoS requirement. Do not use the total LoS as a guide.
 If you have trouble reaching LoS requirements, take a look at the sortie page (for 25, 35) or other players' reports (for event maps) and adjust your equipment accordingly
(Events) Variations in effective LoS between players Edit
During the Summer 2014 event, there were many player reports where players of similar HQ levels have differing effective LoS requirements, leading to confusion among many players. This hinted to a possibility that effective LoS scales to level. Do not be surprised if you level up or reach the next HQ bracket (e.g. HQ lvl 6099, 100+) and fail to reach boss node when you did reach the node the previous sortie.
Some later variation of the formula is then proposed to address the difference.
25 fall formulaEdit
With the advent of the 2014 Fall Event, a new formula for Effective LoS has been devised to account for inconsistencies of the old formula. ^{[1]}^{[2]}
Also known as 25 autumn formula, 25 new formula or new eLoS formula in some places. It is also the eLoS formula or the LoS formula as it has already become a defacto standard on how to calculate (e)los.
 Effective LoS = Dive Bomber LoS x (1.04) + Torpedo Bomber LoS x (1.37) + Carrierbased Reconnaissance Plane LoS x (1.66) + Reconnaissance Seaplane LoS x (2.00) + Seaplane Bomber LoS x (1.78) + Small Radar LoS x (1.00) + Large Radar LoS x (0.99) + Searchlight LoS x (0.91) + √(base LoS of each ship) x (1.69) + (HQ level rounded up to the next multiple of 5) x (0.61)
 √(base LoS of each ship) x (1.69) = Calculate the square root of each ship's LoS (base value without any equipment) separately, then add the values together and multiply by 1.69
 Regarding the HQ Level: For example, if your HQ level is 101~105, use 105. If it's 106~110, use 110. And so on.
new fall simplified Edit
The difference between this one and the 25 fall formula is that it simplified the calculation process a bit by dividing the 25 fall formula with a factor of 1.6841056 and tidying up (round off and matching test result graph) some numbers. However, values obtained from this formula are NOT compatible with 25 fall eLoS values, and thus it is not yet in active use as of today.
The formula to obtain a new fall simplified eLoS value is as follows:
Dive Bomber × 0.6 ＋ Torpedo Bomber × 0.8 ＋ Reconnaissance Aircraft × 1.0 ＋ Reconnaissance Seaplane × 1.2 ＋ Seaplane Bomber × 1.0 ＋ Radar × 0.6 ＋ Search Light × 0.5 － HQ Level ×0.4 ＋ Sum of square root of individual kanmusu LoS value ^{[3]}^{[4]}
Fighters, FCF, SCAMP, as well as Type 3 Command Liaison Aircraft (ASW) values are still unknown, and can be treated with a 0.5 multiplier when factored into the formula here.
ModelEdit
There are two different models applied to calculate the new fall simplified eLoS.^{[5]} Model A is used by tools like Hoppo Alpha, while Model B is used by tools like Electronic Observer.^{[6]}
The difference is that, in model A, after the eLoS value from the kanmusu is added, they are first rounded off before being added up together, and so as with the multiplied HQ level. On the other hand, in model B, kanmusu and HQ level values are added together before being rounded down. According to post from Hoppo Alpha's author, applying model A onto existing data gives a more linear increase in boss entry rate per every point increment, and thus he applied Model A onto Hoppo.Alpha. ^{[5]}
 P.S. The LoS value from kanmusu in the above paragraph = summation of all equipment's LoS value following the rule (equipment LoS value multiply by equipment multiplier) plus the square root of kanmusu's own naked LoS value (without equipment) after.
Unknown Factors in 25 Fall/NFS Formula calculationEdit
Currently, how the 25 fall formula would be affected by Fighters, FCF, SCAMP, ASW Liason Aircraft, Improvement, and Aircraft Proficiency are still undetermined. Some calculators assume equipment in the list have 1.00x of their los value influence on the 25 fall value.
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