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1d
comment Which points in projected raster corresponds to certain latitude,longitude location?
Why? Warping is destructive, it sounds like you just need point value extraction - do you really need to remodel this raster?
1d
answered rasterVis plot3D in R: obtain consistent x-y axes with extent() / projection() shown in RasterLayer object
2d
comment rasterVis plot3D in R: obtain consistent x-y axes with extent() / projection() shown in RasterLayer object
Screenshot? Reproducible example? It is not just an aspect ratio thing is it?
Apr
28
comment Seeking shapefile for Pacific Ring of Fire?
Ha, be brave! Just use a sensible map projection after manually georeferencing this image.
Apr
28
comment Problems to export raster files in R software
Use a different format, this is a terribly limited format. GDAL can deal with non equal x/y and that can be created from R, but I would recommend to just use Geotiff - if you can't get access to rgdal I would ask for help on that.
Apr
25
answered R: Voronoi tesselation from long/lat data?
Apr
25
comment R: Voronoi tesselation from long/lat data?
just give it dummy data voronoi = SpatialPolygonsDataFrame(SP, data=data.frame(x = seq(length(SP)))) or do return(SP) and work with that instead - it's got nothing to do with the coordinate system. If you make a reproducible example someone might fix it.
Apr
25
comment How to colour a SpatialLinesDataFrame with Rainbow
This q is perfectly clear IMO - the default sp plotting is very limited for thematic formatting - you can pass in cols to plot with the "col" argument, but you'll need to map the colour you to each rowin the spdf on your own. But, since the borders of each pixel are collinear you will get a complex pattern of colours based on incremental overlapping borders. Consider ggplot2::fortify(spdf) to go down another alternative for plotting. Make a new question or modify this one with more details about how you want the lines to be formatted.
Apr
24
comment Filtering Small Areas of Shapefiles Using R
I would use rgeos::gArea(mex, byid = TRUE) to get a vectorized area that you can use as an index against the spdf rows. I.e. mex[rgeos::gArea(mex, byid = TRUE) < 1, ]. If you need to decompose those objects first use ?disaggregate.
Apr
21
answered How to deal with two dimensional lat and lon variables in a NetCDF file in R?
Apr
20
comment What are some automated techniques for cleaning bad data from a GPS track log?
A lot of work on this in animal tracking, but the fact is it's a quite technical modelling problem, depending on your needs
Apr
7
comment Rotating ~90° using Two-Point Equidistant projection with Proj4
Great answer! You can also use rasterImage with its angle and interpolation arguments, but you need to correct for the rotation centre (bottom left corner).
Mar
30
comment How can I intentionally corrupt the geometry of a shapefile?
See here for discussion postgis.net/docs/using_postgis_dbmanagement.html#OGC_Validity and look at the GDAL autotest suite for concrete examples with Python trac.osgeo.org/gdal/wiki/TestingNotes
Mar
18
comment Create shapefile connecting points “as the crow flies” in R
If the crow flies a fair distance (I.e. a migratory crow) you'd better use Geo methods like gcIntermediate in geosphere
Mar
16
comment Best file format to manipulate raster data with big length and small width
Probably an actual grid but also store coordinates against the index. NetCDF is suited to this kind of general array storage.
Mar
9
answered Read a table from an ESRI file geodatabase (.gdb) using R
Mar
4
revised R use data in SpatialGrid to create SpatialPoints
pretty sure "deprecate" was intended
Mar
3
comment Creating vector datasets from 3D models
We could do at least some of this with R, keen to explore if you want. My username at Gmail iyi.
Mar
2
answered Is WGS 84 datum, coordinate reference system, or both?
Mar
1
comment Remove certain polygon from SpatialPolygonDataFrame
Be wary of "AREA" attributes. There's no guarantee that's the actual area, right? You can use rgeos::gArea(x, byid = TRUE) to calculate it, and rgdal::spTransform if you need to change projection for that calculation.