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<div><font face="Courier New, Courier, monospace">Caro Alexandre, <br>
<br>
Vc esta usando aquele geotif do outro e-mail? <br>
<br>
### obtem o arquivo <br>
url=("<a
href="http://www.webmapit.com.br/inpe/topodata/download/?ms=137398652719842&fbn=21S465&fsx=3">http://www.webmapit.com.br/inpe/topodata/download/?ms=137398652719842&fbn=21S465&fsx=3</a>")
<br>
download.file(url, destfile = "21S465HN.zip") <br>
### descompacta<br>
system("unzip 21S465HN.zip") <br>
</font><br>
<font face="Courier New, Courier, monospace">### le o raster<br>
require(rgdal) <br>
r <- readGDAL("21S465SN.tif")<br>
<br>
### atribui a projeção longlat e datum WGS83 ao raster. <br>
proj4string(r) <- CRS("+proj=longlat +datum=WGS84")<br>
</font><font face="Courier New, Courier, monospace"><br>
### transformar com é muito ineficiente <br>
### r2 <- spTransform(r, CRS("+proj=utm +zone=23 +south"))<br>
</font><br>
<font face="Courier New, Courier, monospace">### com
projectRaster(), se vc tivesse usando <br>
### r <- raster("21S465SN.tiff")<br>
### r2 <- projectRaster(r, crs=</font><font face="Courier
New, Courier, monospace"><font face="Courier New, Courier,
monospace">CRS("+proj=utm +zone=23 +south"))</font> <br>
### também é muito lento <br>
<br>
### a lentidão é devida ao fato de que extrai-se as <br>
### </font><font face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace">coordenadas </font>de
cada pixel e converte-se cada uma...</font><font face="Courier
New, Courier, monospace"> </font><font face="Courier New,
Courier, monospace"><font face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font face="Courier
New, Courier, monospace"><font face="Courier New, Courier,
monospace"><font face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><font
face="Courier New, Courier, monospace"><br>
<br>
</font></font></font></font></font></font></font></font></font></font></font></font>Att.<br>
Elias<br>
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