Di Malaysia, Manual Saliran Mesra Alam (MSMA) telah mencadangkan dua kaedah
pengiraan untuk mendapatkan luas antara isokron yang telah diamalkan secara
meluas pada masa ini. Mereka adalah kaedah Grid dan kaedah Konvensional. Tetapi,
kaedah-kaedah ini menimbulkan masalah yang tersendiri. Walaupun kaedah Grid
adalah lebih terperinci dan tepat apabila dibandingkan dengan kaedah Konvensional,
ia adalah amat membosankan dan memakan masa. Kaedah Konvensional sebaliknya
adalah lebih mudah untuk digunakan. Tetapi, keputusannya tidak konsisten.
Keputusannya adalah sangat subjektif kerana ia bergantung kepada pengalaman dan
penilaian setiap pengguna. Justeru, kaedah pengiraan baru yang dikenali kaedah
Rangkaian Penyegitiga Tidak Teratur (TIN) telah direka dan dibangunkan dalam
kajian ini untuk meningkatkan pengiraan kaedah Masa-Luas. Kaedah ini adalah
berasaskan komputer dan dengan itu algoritma kaedah TIN dibangunkan. Algoritma
kaedah TIN telah dijelaskan dalam kajian ini. Satu tapak kajian telah dibina dan
lapan set data hujan dikumpul. Semua hasil pengiraan daripada setiap kaedah
disahkan dengan data tapak yang dikumpul untuk membandingkan ketepatannya.
Siasatan ke atas kecekapan dan kebolehpercayaan kaedah-kaedah ini juga dijalankan
dalam kajian ini. Perbandingan ini menunjukkan bahawa kaedah TIN mempunyai
ketepatan yang lebih tinggi. Dalam perbandingan pekali korelasi antara kaedah yang
ada, kaedah TIN mempunyai ketepatan purata 0.988, kaedah Grid mempunyai
ketepatan purata 0.936 dan kaedah Konvensional mempunyai ketepatan purata 0.948.
Apabila mengira peratus perbezaan mereka terhadap data yang dicerap, kaedah TIN
mempunyai perbezaan purata 14.29%, kaedah Grid mempunyai perbezaan purata
25.67% dan kaedah konvensional mempunyai perbezaan purata 24.52%. Apabila
menggunakan aliran puncak bagi perbezaan terhadap data yang diperhatikan,
keputusan menunjukkan bahawa kaedah TIN mempunyai perbezaan purata 3.48%,
kaedah Grid adalah 5.88% dan kaedah konvensional ialah 7.72%. Akhir sekali,
dengan menggunakan jumlah isipadu aliran, kaedah TIN hanya mempunyai 0.19%
perbezaan dengan data yang diperhati, kaedah Grid mempunyai 0.43% dan kaedah
Konvensional mempunyai perbezaan sebanyak 4.80%. Kaedah TIN menunjukkan
ketepatan dan kebolehpercayaan yang lebih tinggi berbanding dengan dua kaedah
yang lain. Selain itu, kajian ini juga menunjukkan bahawa algoritma kaedah TIN
yang baru dibangunkan adalah lebih mudah untuk digunakan, memakan masa yang
kurang dan lebih dipercayai. _______________________________________________________________________
In Malaysia, Manual Saliran Mesra Alam (MSMA) has proposed two calculation
methods to obtain areas between the isochrones that have been widely practiced at
the moment. They are Grid method and Conventional method. However, these
methods pose certain problems of their own. Although the Grid method is more
detail and accurate when compared to the Conventional method, but that is
extremely tedious and time consuming. Conventional method on the other hand is
simpler to use. But, the results are not consistent. The results are very subjective
because it depends on each user’s experience and judgement. Therefore, a new
calculation method named Triangulated Irregular Network (TIN) method has been
designed and developed in this research to improve the Time-Area method
calculation. This method is computer based and thus the algorithm of TIN method
was developed. The algorithm of the TIN method is explained in this research. A
study site was constructed and eight sets of rainfall data were collected. All the
results from each calculation method were verified with the collected site data to
compare their accuracy. Investigation upon their efficiency and reliability were also
presented in this research. The comparison showed that TIN method has higher
accuracy. In the correlation coefficient comparison among the methods, TIN
method has average accuracy of 0.988, Grid method has average accuracy of 0.936
and Conventional method has average accuracy of 0.948. When calculating their
difference against the observed data in percentage, TIN method has average
difference of 14.29%, Grid method has average difference of 25.67% and
Conventional method has average difference of 24.52%. When using the peak flow
comparison for the difference against the observed data, the results shows that TIN
method has average difference of 3.48%, Grid method has average difference of
5.88% and Conventional method has average difference of 7.72%. Lastly, the
methods were compared using the total flow volume. It was demonstrated that the
TIN method has different of 0.19%, Grid method has different of 0.43% and
Conventional method has different of 4.80% when compared to the observed data.
The TIN method has the highest accuracy and reliability among the three methods.
Besides, this research also showed that the newly developed TIN method algorithm
is easier to use, less time consuming and more reliable.
Estimation of time of concentration using triangulated irregular network method_Ewe Teik Tsia_REDAC_2015_MYMY