[R-sig-Geo] converting the projection

[Kyongho Son]

Sorry and thanks, Mike
I can not share all codes and data since the original data are huge.
I copied the scripts that I used to reproject one of rasters and then make sure that they have same projection

 Then clip a large raster with a small raster. However, I got the error messages, the two raster maps are not overlap.

They should overlap if the projection was correct.



# east US map tree phenology map
tmp<-raster("../../obs/eMODIS_East_SOSTAvg0114_v1/sostavg0114")

proj4string(tmp)
[1] "+proj=laea +lat_0=-100 +lon_0=6370997 +x_0=45 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0"

# small watershed boundary map in NY state
bb<-raster("../../obs/gis/bb_soil_def_map.tif")
proj4string(bb)
[1] "+proj=utm +zone=18 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0"

ex <- projectExtent(bb,  projection(tmp))

> ex
class       : RasterLayer
dimensions  : 598, 515, 307970  (nrow, ncol, ncell)
resolution  : 30.12012, 14.94084  (x, y)
extent      : 6691756, 6707267, 9941473, 9950408  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=laea +lat_0=-100 +lon_0=6370997 +x_0=45 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0


c<-crop(tmp,  ex)

Error in .local(x, y, ...) : extents do not overlap




*Kyongho Son*
Postdoctoral Fellow
Research Foundation of The City University of New York


________________________________
From: Michael Sumner <mdsumner at gmail.com>
Sent: Tuesday, September 19, 2017 8:32 PM
To: Kyongho Son; RsigGeo
Subject: Re: [R-sig-Geo] converting the projection

Keep on list please.

Share code to demonstrate so we can see the problem.  Use projectRaster(a, b)  for alignment,  try crop(b,  ex,  snap = "out")  for inclusive crop.

And apologies I wrote clip instead of crop earlier.

Cheers,  Mike

On Wed, 20 Sep 2017, 07:42 Kyongho Son <kkyong77 at hotmail.com<mailto:kkyong77 at hotmail.com>> wrote:

I did the exact same way, but the output of the reprojection of 'a' raster did not properly align with 'b' raster.





*Kyongho Son*
Postdoctoral Fellow
Research Foundation of The City University of New York


________________________________
From: Michael Sumner <mdsumner at gmail.com<mailto:mdsumner at gmail.com>>
Sent: Tuesday, September 19, 2017 5:03 PM
To: Kyongho Son; r-sig-geo
Subject: Re: [R-sig-Geo] converting the projection

Try projecting just the extent
library(raster)
ex <- projectExtent(a,  projection(b))
clip(b,  ex)

where a,  b are your two raster.

Cheers,  Mike

On Wed, 20 Sep 2017, 06:18 Kyongho Son <kkyong77 at hotmail.com<mailto:kkyong77 at hotmail.com>> wrote:

Hi I have two raster data sets but they have two datum and projection.

I would like to convert one to the other since I would like to clip the one raster using the other raster.

they should have same projections.


proj4string(bb)
[1] "+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"
proj4string(SOSTavg)

 proj4string(SOSTavg)
[1] "+proj=laea +lat_0=-100 +lon_0=6370997 +x_0=45 +y_0=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"


Thanks,

Kyongho








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Dr. Michael Sumner
Software and Database Engineer
Australian Antarctic Division
203 Channel Highway
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