# [R] Best method for comparing rectangles sections of beach

Jhope jeanwaijang at gmail.com
Mon Oct 8 12:02:17 CEST 2012

```Hi R-listers,

I am trying to compare sections of the beach separated from the HTL to the
Veg (east to west), separated into indices (-5 to 30m), HTLIndex.  Cross
parallel (north to south) are major beach sections (Rayos 1, 2, 3, 4 and
MNB). I am thinking to do an ANOVA for each independent rectangle of beach
(not exactly but will be treated as). The HTL from (0-5m) in Rayo 1 is one
rectangle of beach; (0-5m) in Rayo 2 is another... etc.

I was considering an 2-way anova with interactions - see below. But this
does not identify each section of the beach by 5 meters and Rayos.

1) What is the best way to compare these beach rectangle sections?
2) Each Rayo is a little bit different in size but for management purposes,
it is identified by these sections (leave alone or use), so maybe ANOVA is
appropriate?
3) Script suggestions greatly appreciated.

----------------

summary(aov(HSuccess ~ HTLIndex*Aeventexhumed, data=data.to.analyze))

Df Sum Sq Mean Sq F value  Pr(>F)
HTLIndex                6  0.691 0.11524   3.023 0.00937 **
Aeventexhumed           2  0.106 0.05308   1.393 0.25329
HTLIndex:Aeventexhumed 11  0.376 0.03418   0.897 0.54645
Residuals              98  3.736 0.03812
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
5 observations deleted due to missingness
Warning message:
In model.matrix.default(mt, mf, contrasts) :
variable 'Aeventexhumed' converted to a factor

---------
ST4 Shells
1         8.1A Nov. 26, 2010     14       8             A   6   0   1  98
1     72
2        10.1A Nov. 26, 2010     13      10             A   4   0   0 109
1     74
3        14.1A Nov. 18, 2010     20      14             A   6   0   2  26
11    106
4        19.1A Nov. 22, 2010     79      19             A   0   0   0   0
0    102
5        23.1A Nov. 20, 2010     34      23             A 135  23   1   6
0    125
6        24.1A Nov. 28, 2010     34      24             A 660   0   2   0
0      4
Aeventexhumed   Veg
1          3       72         2       0       178       8.1     14
A  9.75
2          4       74         0      21       188      10.1     13
A 16.34
3          1      106         1     165       151      14.1     20
A  3.15
4          1      102         0       0       102      19.1     79
A  5.70
5         48      125         0       0       290      23.1     34
A 12.20
6          0        4         0      36       666      24.1     34
A  4.82
Berm   HTL Estuary   Rayos NotHatched DevelopIndex VegIndex  HTLIndex
1   NA  4.66      NA Rayos.1        106     3.865169   (6-10)     (0-5)
2   NA -2.47      NA Rayos.1        114     4.920213  (16-20) (-5-(-1))
3   NA 16.00      NA Rayos.2         45     5.622517    (0-5)   (16-20)
4   NA    NA    11.8 Rayos.2          0     1.000000   (6-10)      <NA>
5   NA  2.35      NA Rayos.3        165     3.406897  (11-15)     (0-5)
6   NA 22.85      NA Rayos.3        662     5.981982    (0-5)   (21-25)

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