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POR extract raster function not working
 

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  1. POR extract raster function not working
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    <p>I am having trouble with the extract function in the raster package. The raster is not empty, but when I perform the extract function all the values come back as NAs. I can plot the points over the raster fine and they show up in the same location. </p> <pre><code>library(dismo) library(raster) #Import CSV File file &lt;- paste("C:/Michelle/Michelle/R/CuskPA_Sept12_2013_1.csv", sep=" ") #read file cusk &lt;- read.table(file, header=TRUE, sep=',') cusks&lt;- subset(cusks, SlongDD!=0 &amp; SlatDD!=0) cuskll &lt;-cusks[,24:25] #import raster salvar &lt;- raster("C:/Michelle/Michelle/R/Variables/salvar") ext &lt;-extent(-67.6, -64.9, 41.0, 44.7453) salvarc &lt;-crop(salvar, ext) #extract from raster psalvar &lt;- extract(salvarc, cuskll) </code></pre> <p>This is what I get when I'm finished the extraction</p> <pre><code>head(psalvar) [1] NA NA NA NA NA NA summary(psalvar) Mode NA's logical 3859 </code></pre> <p>The raster does not show up as empty.</p> <pre><code>&gt; salvar class : RasterLayer dimensions : 334, 240, 80160 (nrow, ncol, ncell) resolution : 0.01121539, 0.01121539 (x, y) extent : -67.59662, -64.90493, 41.00048, 44.74642 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs data source : in memory names : salvar values : 0.01655413, 2.137321 (min, max) </code></pre> <p>Here is an example of the lat/longs in the file</p> <pre><code>head(cuskll) SlatDD SlongDD 1 44.41533 -66.07883 2 44.41167 -66.07733 3 44.44883 -66.07433 4 44.47067 -66.01217 5 44.47050 -66.01183 6 44.47633 -66.01450 </code></pre>
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    1. USGreenlawM
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    1. COHave you tried coercing your data into an sp object? coordinates(cuskll) <- ~SlongDD+SlatDD
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      1. POR extract raster function not working
      1. USJeffrey Evans
    2. COWhat does it look like if you plot it, pretty easy to see if you should be getting something. plot(salvar);points(cuskll); It looks to me like you've mixed up Longitude with Latitude, so try cuskll <-cusks[,25:24] and proceed as before.
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      1. POR extract raster function not working
      1. USmdsumner
    3. COCan you plot, or otherwise work with `salvar` ? If so, then can you do the same with `csalvar` ? And if that's OK, then the extraction step is almost certainly the culprit.
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      1. POR extract raster function not working
      1. USCarl Witthoft
 

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