180 degree offset of r.slope.aspect

[Ronald E. Thomas]

GRASSuser's,
	I couldn't use the solutions suggested by Mr. Jianping Xu to transform
my ASPECT map into an AZIMUTH map because I used the new r.slope.aspect,
which "slices & dices" elevation into 360 degrees of aspect, not just 24
quadrants.
So, I actually had to do some work myself, and developed the following
script that uses 'r.reclass' to turn a 360 degree aspect map ( 360 = east,
rotation counter-clockwise) into a standard azimuth map (360 = north,
rotation clockwise).

I call the file "as2az", rename as you please; to use:
	
	as2az <aspect_map> <azimuth_map>

begin as2az
################################# CUT HERE  ###########################
#! /bin/sh
# Test to confirm you are running GRASS
if [ -z "$GISRC" ]
then
echo "You must be using GRASS to be using this program!!"
echo 
echo "                 exiting"
exit 1
fi

r.reclass i=$1 o=$2 << EOF
0=0	no aspect
89=1	1 degree from north
88=2	2 degrees from north
87=3	3 degrees from north
86=4	4 degrees from north
85=5	5 degrees from north
84=6	6 degrees from north
83=7	7 degrees from north
82=8	8 degrees from north
81=9	9 degrees from north
80=10	10 degrees from north
79=11	11 degrees from north
78=12	12 degrees from north
77=13	13 degrees from north
76=14	14 degrees from north
75=15	15 degrees from north
74=16	16 degrees from north
73=17	17 degrees from north
72=18	18 degrees from north
71=19	19 degrees from north
70=20	20 degrees from north
69=21	21 degrees from north
68=22	22 degrees from north
67=23	23 degrees from north
66=24	24 degrees from north
65=25	25 degrees from north
64=26	26 degrees from north
63=27	27 degrees from north
62=28	28 degrees from north
61=29	29 degrees from north
60=30	30 degrees from north
59=31	31 degrees from north
58=32	32 degrees from north
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6=84	84 degrees from north
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4=86	86 degrees from north
3=87	87 degrees from north
2=88	88 degrees from north
1=89	89 degrees from north
360=90	east 
359=91	91 degrees from north
358=92	92 degrees from north
357=93	93 degrees from north
356=94	94 degrees from north
355=95	95 degrees from north
354=96	96 degrees from north
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347=103	103 degrees from north
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336=114	114 degrees from north
335=115	115 degrees from north
334=116	116 degrees from north
333=117	117 degrees from north
332=118	118 degrees from north
331=119	119 degrees from north
330=120	120 degrees from north
329=121	121 degrees from north
328=122	122 degrees from north
327=123	123 degrees from north
326=124	124 degrees from north
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323=127	127 degrees from north
322=128	128 degrees from north
321=129	129 degrees from north
320=130	130 degrees from north
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318=132	132 degrees from north
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316=134	134 degrees from north
315=135	135 degrees from north
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310=140	140 degrees from north
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298=152	152 degrees from north
297=153	153 degrees from north
296=154	154 degrees from north
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288=162	162 degrees from north
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286=164	164 degrees from north
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282=168	168 degrees from north
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280=170	170 degrees from north
279=171	171 degrees from north
278=172	172 degrees from north
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276=174	174 degrees from north
275=175	175 degrees from north
274=176	176 degrees from north
273=177	177 degrees from north
272=178	178 degrees from north
271=179	179 degrees from north
270=180	south
269=181	181 degrees from north
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182=268	268 degrees from north
181=269	269 degrees from north
180=270	west 
179=271	271 degrees from north
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91=359	359 degrees from north
90=360	north
EOF
 
##############################end of file ############################