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1d
comment How to calculate a curve distance between two xyz points?
Is the curve just the curvature due to depth or also the curvature of the Earth? (You might be surprised how little it matters, but all depends on the extent and the data itself).
2d
comment Plotting Raster in R gives error
Check for sure that the right paired file/s exist, this must have been partnered with a .hdr file - make sure it's there too. Are you sure you didn't copy the .bil from somewhere, without also copying the .hdr? (There may be other auxiliarly files). I'm guessing this driver is the one involved (via rgdal): gdal.org/frmt_various.html#EHdr Also best not to use "setwd", but rather use file.path() to create full paths.
Feb
7
comment Tearing of SpatialLinesDataFrame and problem with gClip function
Try raster::erase or raster::intersect
Feb
5
comment Spatial index in R - Performance enhancement on geospatial processing
rgeos has some of these facilities, see ?rgeos::poly_findInBoxGEOS - otherwise put your loot in Postgres/PostGIS or similar, do the work there and read from the db back to R.
Feb
5
comment Project NetCDF file using GDAL or QGis
I don't see any error for the process, so did the output not work? (the lookup UOM thing probably doesn't matter). Your "RAIN_MM_1hour_ac_proj.nc" is a GeoTIFF, since you didn't specify the output format with "-of NetCDF" (GDAL doesn't care about extensions, but helpfully reminded you). Why are you trying to warp a file that's pretty clearly in Long-Lat to Long-Lat? I don't understand why you have any work to do here (??). You maybe want to gdal_translate with -a_srs argument to fill in the metadata.
Feb
4
comment Failure of the code calling the function “rasterize” in R: NAs or no slots
r.ext does not have the the same extent as r.ext <- raster(extent(shp.prj)) - so that presumably is not the actual code involved here. (You could just do raster(shp.prj) to avoid the need for projection()<-). Otherwise I would try rasterize(shp.prj, r.ext, field=shp.prj$land_cover_type)
Feb
3
comment create a grid and extract species and climate data
We need much more information in order to help you. With the raster package it's easy to create such a grid, and extract etc. but you'll need some idea of how it works: see the vignette with library(raster); vignette("Raster")
Jan
26
comment Spplot SpatialPolygonDataFrame and SpatialGridDataFrame
I think you maybe trying to merge these objects(?) or convert the grid to polygons(?) when all you want is to plot. Does this work? image(SGDF); plot(SPDF, add = TRUE); Otherwise as Spacedman says, please just show us the code
Jan
21
comment R calculate raster cell size in map units
There's no point to convert to polygon after warping since every pixel is the same size in that coordinate system, by definition. It's impossible to answer this generally with a concise solution since there are so many details that matter about where and how extensive etc., but it's more sensible to convert to polygon from the source raster, and use the n option in rasterToPolygons, and then project, to ensure sufficient vertices to carry the polygons into the new coordinate system.
Jan
15
comment How to compute max and min coordinates for multiple polygons?
Nice! ---------------------
Jan
10
comment Same coordinate system - shapefiles don't overlap
"Same coordinate system" is the boner here. I don't think it's true.
Jan
10
comment Identify Hawaiian coordinate system
There are at least 5 State Plane coordinate systems for Hawaii and there's no reason to believe any of them are it. Where did you come across this? The actual source is always the best place to look, the evidence comes in many forms.
Jan
3
comment GDAL “Simple Tiling” (Or yet another - how do I tile question)
I think you could use gdal.org/gdal_retile.html
Dec
28
comment Visualizing shapefiles on web using SHINY package of R with PostGIS?
It's pretty similar to how you plot and analyse data from PostGIS in R. Once you got all that working you can build it into a Shiny page easily enough. The great thing about Shiny is it requires very little modification of working code, you just hook up the UI and the server to run your functions.
Dec
26
comment How to find the cell location index of a raster using Lat long information?
Can simplify to rowColFromCell(ras, cellFromXY(ras, cbind(-82.8,35.2)))
Dec
23
comment Buffer from Point or Polygon with Information from Raster
You can modify the 'directions' argument to get exactly the cells you want relative to the centre, I think that can cover the "linear" modification you want?
Dec
23
comment R: extract values from raster stack and aggregate results
There's no time wasted here.
Dec
23
comment Geo-Referencing an image from google maps with gdal_translate
The corner coordinates for u_llr must be in the coordinate system used by the image, not longitude/latitudes.
Dec
21
comment How to read file geodatabase with Binary field in R?
Scratch that, I believe your data is a raster. R can't read the geodatabase raster (neither can GDAL). Get them to provide a useable format is the only option I'm afraid. When you read it as vector (or convert to shapefile) I think you just get the bounding box polygon.
Dec
21
comment How to read file geodatabase with Binary field in R?
Try "drop_unsupported_fields=TRUE" see ?readOGR