Hot answers tagged

9

From the links posted as comments I identified a couple of misconceptions I had about projections and gathered this quick summary. It should be mentioned that many projections don’t truly preserve any attribute. Their intent is typically to minimize all types of distortion thereby not eliminating it in any specific property. Jack of all trades, master of ...


7

First install QGIS plugin "Affine Transformation" from Plugins > Manage and Install Plugins.. Then start editing and navigate to vector > Geoprocessing Tools > Affine Transformation. Add your latitude value in 'y+' as encircled in the screen shot.


5

You need to make a spatial points object and then reproject that: library(sp) library(maptools) data(wrld_simpl) wrld_simpl.trans <- spTransform(wrld_simpl, CRS = ("+proj=moll +lon_0=0 +x_0=0 +y_0=0")) plot(wrld_simpl.trans, col = 'lightgray')) latitudes <- c(-30, 0, 20, 50) longitudes <- c(-20, 10, 50, 80) Make an SPDF: pts <- ...


3

What defines which projection is a polygon based upon, and therefore which projection should apply to it? For these vertices, are the right polygons the left or the right ones? That depends on what purpose the polygons are going to used for. If their areas matter, then you should build them in an equal area projection like Albers. If 90 degree ...


2

You can see a demo in action to illustrate. The thing to keep in mind are: load Proj4js library and the local EPSG code proj4js declaration from http://epsg.io website get the ol.proj.projection object and set it extent (for managing map resolution) var extent = ol.proj.transformExtent([-8.74, 49.81, 1.84, 60.9], 'EPSG:4326', 'EPSG:27700'); var ...


2

I usually use a function to create WMS Layers to avoid redundances. function Tile(options){ return new ol.layer.Tile({ name: options.name || 'Layer', visible: options.visible === false ? false : true, source: new ol.source.TileWMS({ crossOrigin: 'anonymous', url: options.url, params: { ...


2

In ArcGIS you can use batch processing to run the re-projection tool on a large dataset. If it doesn't work on rasters than you can use the model builder to achieve the same thing by using iterators as shown here. QGIS also has a batch processing interface but I haven't used it myself, so I'm not sure how effective that is. Your best bet might be to just ...


2

No problem for QGIS: Write the coordinates of both points in decimal degrees into a text file: Name East North Tokyo 139.75 35.6667 NewYork -73.96667 40.78333 Load the points file as delimited text Create a aeqd projection on one point using a sphere: +proj=aeqd +lat_0=40.78333 +lon_0=-73.96667 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m +no_defs ...


2

Try with other zone it has no problem, I guess GDAL cannot wrap it outside. gdalwarp -t_srs '+proj=utm +zone=12 +datum=WGS84 +units=m +no_defs' test.tif test_utm1.tif


2

las2las flightline_002.las --a_srs EPSG:32632 doesn't modify flightline_002.las. Rather, it creates a new file called output.las with the spatial reference information. output.las is the default value of the -o [ --output ] option available in las2las. To specify the new filename, use the following construction: las2las --a_srs EPSG:32632 ...


2

This is happening because in your manual workflow your feature class has a different coordinate system than the data frame, so there is a transformation on-the-fly going on. However, in your automated workflow you are reprojecting the feature class and then calculating area. Depending on the shape & size of the polygon, and the location, these two ...


1

This needs several steps: The borders are freely available from Natural Earth Using QGIS, you can reproject the data to the Gall-Peters projection. You need to create a custom CRS for it: "+proj=cea +lon_0=0 +x_0=0 +y_0=0 +lat_ts=45 +ellps=WGS84 +datum=WGS84 +units=m +no_defs" Exporting to SVG is not supported directly, but you can install the ...


1

A couple things might be happening here. You have a transparency on the layer (unlikely). You have a stretch type defined in the symbology for the raster. This might be standard deviation: Set it to None and see if that makes any difference.


1

Looks like ESRI decided to define their own projection parameters: http://osgeo-org.1560.x6.nabble.com/Question-about-Krovak-projection-and-ESRI-XY-Plane-Rotation-parameter-td4291471.html There has also been some discussion on the GDAL list recently: http://comments.gmane.org/gmane.comp.gis.gdal.devel/42132 I suspect the raster package is applying some ...


1

To effectively use shapely it is important to first project your coordinates into a projected coordinate system that is appropriate to your region, for example, epsg:27700 if you are based in the UK. A good way to do this is using pyproj: import pyproj as proj # setup your projections crs_wgs = proj.Proj(init='epsg:4326') # assuming you're using WGS84 ...



Only top voted, non community-wiki answers of a minimum length are eligible