[R-sig-Geo] problems with points2grid
Robert J. Hijmans
r.hijmans at gmail.com
Tue Nov 2 17:53:18 CET 2010
Yan,
An alternative approach, if you want to force regularly spaced points
to a grid that you know the parameters of, you could first create that
grid and then link the values by cell numbers
library(raster)
r <- raster(ncol=10, nrow=10, xmn=.. xmx= etc)
cells <- cellFromXY(r, xy)
r[cells] <- value
(not to be confused with pointsToRaster for random like distributions
with perhaps multiple points per cell).
Robert
On Mon, Nov 1, 2010 at 7:03 PM, Yan Boulanger <yan_boulanger at hotmail.com> wrote:
>
>
>
> Hi
> everyone,
>
>
>
> This seems
> (again) a very simple question but I’m not able to get this work. I have point
> data from the Canadian National Forest Inventory. This inventory was realized
> using a grid of 20 regularly spaced points. Even though I have access to the
> point data, I don’t have the grid data. Actually, I would like to use the grid
> data in order to do some moving window analyses. Plotting the point makes it
> obvious that these were generated using a grid. I used the points2grid in order
> to convert Grid. However, I get this error message :
>
>
>
> library(rgdal)
>
> nfi_centroid
> <- readOGR(".", "nbie")
>
> coord_nficentroid<-coordinates(nfi_centroid)
>
> grid_new
> <- points2grid(SpatialPoints(coord_nficentroid),
> tolerance=sqrt(.Machine$double.eps), round=NULL, fuzz.tol=3)
>
>
>
> suggested
> tolerance minimum: 0.40961317562634
>
> Erreur dans
> points2grid(SpatialPoints(coord_nficentroid), tolerance =
> sqrt(.Machine$double.eps), :
>
> dimension 1 : coordinate intervals are not
> constant
>
>
>
> However,
> one could see that intervals are constant except, of course, when points fall
> in water. I tried with a subset of points that excluded any point skipping due
> to water and got that same result. I’m a little bit puzzled… I’m surely missing
> something!
>
>
>
> Thanks for
> the help!
>
>
>
> Yan
>
>
>
> Using R
> 2.11.1
>
>
>
> The original
> projection was :
>
> Projected
> Coordinate System: NAD_1983_Albers
>
> Projection:
> Albers
>
> False_Easting:
> 0,00000000
>
> False_Northing:
> 0,00000000
>
> Central_Meridian:
> -95,00000000
>
> Standard_Parallel_1:
> 49,00000000
>
> Standard_Parallel_2:
> 77,00000000
>
> Latitude_Of_Origin:
> 49,00000000
>
> Linear
> Unit: Meter
>
>
>
> Geographic
> Coordinate System: GCS_North_American_1983
>
> Datum:
> D_North_American_1983
>
> Prime
> Meridian: Greenwich
>
> Angular
> Unit: Degree
>
>
>
> Here’s
> a subset of the point data for New Brunswick.
>
> coordinates Id
>
> 1 (2200320, 384479) 0
>
> 2 (2192230, 366274) 0
>
> 3 (2095010, 343514) 0
>
> 4 (2165910, 356022) 0
>
> 5 (2076780, 351499) 0
>
> 6 (2184140, 348078) 0
>
> 7 (2202370, 340149) 0
>
> 8 (2157810, 337828) 0
>
> 9 (2113240, 335544) 0
>
> 10 (2149700, 319642) 0
>
> 11 (2068680, 333298) 0
>
> 12 (2176040, 329890) 0
>
> 13 (2131470, 327586) 0
>
> 14 (2105140, 317356) 0
>
> 15 (2060570, 315108) 0
>
> 16 (2167930, 311709) 0
>
> 17 (2086910, 325320) 0
>
> 18 (2194270, 321966) 0
>
> 19 (2042340, 323093) 0
>
> 20 (2078790, 307135) 0
>
> 21 (2186160, 303791) 0
>
> 22 (2123360, 309404) 0
>
> 23 (2159810, 293539) 0
>
> 24 (1981530, 284526) 0
>
> 25 (2034220, 304904) 0
>
> 26 (2141590, 301465) 0
>
> 27 (1989650, 302709) 0
>
> 28 (2222600, 287994) 0
>
> 29 (2070670, 288956) 0
>
> 30 (2097020, 299175) 0
>
> 31 (2052450, 296924) 0
>
> 32 (2007870, 294710) 0
>
> 33 (2115250, 291229) 0
>
> 34 (2088900, 281003) 0
>
> 35 (2151690, 275374) 0
>
> 36 (1963300, 292533) 0
>
> 37 (2178040, 285625) 0
>
> 38 (2026100, 286723) 0
>
> 39 (1973390, 266350) 0
>
> 40 (2206340, 251692) 0
>
> 41 (2133470, 283295) 0
>
> 42 (2169910, 267467) 0
>
> 43 (2017970, 268551) 0
>
> 44 (2196260, 277725) 0
>
> 45 (2044320, 278750) 0
>
> 46 (1999750, 276532) 0
>
> 47 (2188130, 259573) 0
>
> 48 (2036190, 260582) 0
>
> 49 (2054410, 252625) 0
>
> 50 (2107120, 273062) 0
>
> 51 (1955170, 274350) 0
>
> 52 (2214470, 269839) 0
>
> 53 (2062550, 270788) 0
>
> 54 (2125340, 265134) 0
>
> 55 (2143560, 257219) 0
>
> 56 (1991610, 258362) 0
>
> 57 (2232690, 261965) 0
>
> 58 (2080770, 262838) 0
>
> 59 (2250900, 254106) 0
>
> 60 (1965250, 248184) 0
>
> 61 (2224550, 243825) 0
>
> 62 (2072630, 244684) 0
>
> 63 (2098990, 254904) 0
>
> 64 (2109060, 228836) 0
>
> 65 (2161770, 249317) 0
>
> 66 (2009830, 250387) 0
>
> 67 (2269110, 246260) 0
>
> 68 (2117200, 246982) 0
>
> 69 (2331860, 240924) 0
>
> 70 (2179990, 241429) 0
>
> 71 (2028050, 242424) 0
>
> 72 (2135420, 239072) 0
>
> 73 (1983470, 240202) 0
>
> 74 (2242760, 235970) 0
>
> 75 (2090840, 236753) 0
>
> 76 (2198200, 233554) 0
>
> 77 (2046270, 234474) 0
>
> 78 (2305520, 230608) 0
>
> 79 (2260960, 228130) 0
>
> 80 (1957100, 230026) 0
>
> 81 (2234610, 217843) 0
>
> 82 (2315560, 204691) 0
>
> 83 (2163690, 205166) 0
>
> 84 (2216410, 225692) 0
>
> 85 (2064480, 226536) 0
>
> 86 (2323720, 222803) 0
>
> 87 (2171840, 223293) 0
>
> 88 (2019900, 224274) 0
>
> 89 (2279170, 220303) 0
>
> 90 (2153630, 231176) 0
>
> 91 (2001690, 232232) 0
>
> 92 (2100910, 210701) 0
>
> 93 (1948950, 211877) 0
>
> 94 (2127270, 220933) 0
>
> 95 (1975320, 222049) 0
>
> 96 (2082690, 218612) 0
>
> 97 (2190050, 215424) 0
>
> 98 (2038110, 216330) 0
>
> 99 (2297370, 212490) 0
>
> 100 (2145480, 213043) 0
>
> 101 (2252810, 210010) 0
>
> 102 (2208250, 207567) 0
>
> 103 (2056330, 208398) 0
>
> 104 (2165550, 161088) 0
>
> 105 (2281040, 176281) 0
>
> 106 (2129150, 176804) 0
>
> 107 (2272870, 158190) 0
>
> 108 (2271010, 202188) 0
>
> 109 (2119110, 202803) 0
>
> 110 (2074540, 200480) 0
>
> 111 (2226450, 199725) 0
>
> 112 (2066370, 182357) 0
>
> 113 (2147350, 168939) 0
>
> 114 (2254680, 165986) 0
>
> 115 (2181890, 197303) 0
>
> 116 (2029960, 198195) 0
>
> 117 (2289210, 194380) 0
>
> 118 (2137320, 194919) 0
>
> 119 (2244650, 191898) 0
>
> 120 (2092740, 192575) 0
>
> 121 (1940780, 193737) 0
>
> 122 (2200090, 189452) 0
>
> 123 (2048160, 190269) 0
>
> 124 (2155520, 187049) 0
>
> 125 (2262850, 184082) 0
>
> 126 (2110950, 184683) 0
>
> 127 (2218290, 181616) 0
>
> 128 (2173720, 179191) 0
>
> 129 (2120980, 158699) 0
>
> 130 (2236480, 173795) 0
>
> 131 (2084580, 174458) 0
>
> 132 (2191920, 171347) 0
>
> 133 (2039990, 172149) 0
>
> 134 (2299230, 168494) 0
>
> 135 (2102780, 166572) 0
>
> 136 (2210120, 163517) 0
>
> 137 (2058200, 164243) 0
>
> 138 (2228310, 155700) 0
>
> 139 (2094600, 148470) 0
>
> 140 (2076400, 156350) 0
>
> 141 (2220130, 137616) 0
>
> 142 (2068220, 138252) 0
>
> 143 (2183750, 153250) 0
>
> 144 (2112800, 140604) 0
>
> 145 (2139170, 150840) 0
>
> 146 (2246500, 147898) 0
>
> 147 (2201940, 145427) 0
>
> 148 (2050020, 146139) 0
>
> 149 (2157370, 142996) 0
>
> 150 (2264680, 140109) 0
>
> 151 (2193750, 127345) 0
>
> 152 (2203740, 101476) 0
>
> 153 (2175560, 135164) 0
>
> 154 (2130990, 132751) 0
>
> 155 (2238310, 129820) 0
>
> 156 (2086410, 130378) 0
>
> 157 (2149180, 124911) 0
>
> 158 (2256490, 122037) 0
>
> 159 (2104610, 122518) 0
>
> 160 (2211930, 119542) 0
>
> 161 (2060020, 120164) 0
>
> 162 (2167370, 117086) 0
>
> 163 (2122800, 114671) 0
>
> 164 (2230120, 111751) 0
>
> 165 (2078220, 112296) 0
>
> 166 (2187320, 65377.6) 0
>
> 167 (2160920, 55121.2) 0
>
> 168 (2185550, 109274) 0
>
> 169 (2140980, 106838) 0
>
> 170 (2248300, 103974) 0
>
> 171 (2096410, 104442) 0
>
> 172 (2240090, 85921.7) 0
>
> 173 (2088200, 86376) 0
>
> 174 (2124570, 70720.6) 0
>
> 175 (2159170, 99019) 0
>
> 176 (2114600, 96602.2) 0
>
> 177 (2221920, 93691.9) 0
>
> 178 (2070010, 94223.2) 0
>
> 179 (2177350, 91213.9) 0
>
> 180 (2132780, 88774.2) 0
>
> 181 (2195530, 83422.5) 0
>
> 182 (2150960, 80962.3) 0
>
> 183 (2106390, 78541.3) 0
>
> 184 (2213710, 75643.1) 0
>
> 185 (2169140, 73162.6) 0
>
> 186 (2205490, 57605.4) 0
>
> 187 (2079990, 68319) 0
>
> 188 (2142750, 62914.6) 0
>
> 189 (2116350, 52677.1) 0
>
> 190 (2179100, 47343.4) 0
>
> 191 (2134520, 44877.3) 0
>
> 192 (2170870, 29318.1) 0
>
> 193 (2152700, 37090.6) 0
>
> 194
> (2198950, -4186.01) 0
>
>
>
> Yan Boulanger
> Dendrolab - Datation de bâtiments patrimoniaux par dendrochronologie
> www.dendrolab.ca
> info at dendrolab.ca
>
>
>
> Université du Québec à Rimouski
> Département de Biologie
> Centre d'études nordiques
> 300, allée des Ursulines
> Rimouski, PQ G5L 3A1
> (418) 723-1986 poste 1482
>
>
>
> [[alternative HTML version deleted]]
>
>
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