iCharts Discussions

chrome · Yellow Belt Joined: 28 Dec 2009 Posts: 645

Hi PT/ ST,

was just checking EOD charts on Charts premium and the one from your chartfeed link...Have found that Bank nifty EOD charts on both the charts are giving different values of 200 EMA (value 10996 on chartfeed link and value 10905 on charts premium for 200 EMA)..the link for chartfeed which i am visiting is this http://chartfeed.icharts.in/ShowChart.php?symbol=banknifty&period=Daily&pr_period=1Y&chart_size=800&uind1=EMA&uind1_param=20&uind2=EMA&uind2_param=200&lind1=SStoch&lind1_param=39,1&lind3=RSI&lind3_param=14&chart_type=CANDLES

pls check.

SID2060 · White Belt Joined: 04 Nov 2009 Posts: 319

banknifty ema 200

Chartfeed 10996

Chart premium 10905

Screener (EOD) 10893.38

I have seen such difference in almost every scrip and index. Plz resolve the matter asap.

Regards,
Sid Smile

SwingTrader · Posted: Sun Jan 02, 2011 10:31 am Post subject:

To understand why there is a difference in the values of EMA you will first have to understand how EMA gets computed. EMAs use a weighting factor to give more importance to recent values (and lesser importance to old values). EMAs use ALL data one provides it (unlike SMAs that use only fixed number of values for its computation).

Now coming to the point....JCharts & Charts (Premium) (or chart feed etc) use different number of data points (number of days/weeks/months of data) for EMA computation. This number of data points depends on how much data you are loading the chart. In JCharts this means your "Historical Intraday Timeframe" setting. If you select 3 yrs here then 3 yrs of data is used for EMA computation. Whereas in Charts (Premium) or chart feed link we internally use around 8 yrs of data for EMA computation - this is fixed. So JCharts & Charts (Premium) / Chart feed EMA values will not match.

Check SMA values, they should match everywhere. EMAs are a totally different animal Very Happy

SID2060 · White Belt Joined: 04 Nov 2009 Posts: 319

Dear st,

If I take DLF one year data and then compute ema 14 and than i again compute ema 14 but from 6 month historical data of DLF. Does the ema14 will be different for full year and half yearly timeframe?

SwingTrader · Posted: Sun Jan 02, 2011 11:12 am Post subject:

SID2060 · White Belt Joined: 04 Nov 2009 Posts: 319

Dear ST,

I will compute ema14 today and will see the difference. Also i think u should not compute ema from 8 year historical data in chart (premium) because if any adjustment like split or bonus is missed than it will have an adverse effect on the computed ema. I had reported such incidence in kfa where stock split happened in the past but was not adjusted and wrong emas were calculated. I just wana say that i think 2 or 3 years data is more than enough to compute ema 200 and all othe emas.

I have made screener (eod) for american stock mkt comprising of components of dowjones, s&p 500, nasdaq 100, s&p 100 and other most liquid100 etf's like spy, qqqq, dia,gld, slv,sds etc and i use 1 year timeframe data to compute ema 200 and all other emas. In one year the american mkt have 253 traded days this time.

Regards,
Sid

SwingTrader · Posted: Sun Jan 02, 2011 9:29 pm Post subject:

aromal · White Belt Joined: 22 Mar 2010 Posts: 302