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Questions tagged [coordinate-system]

A reference framework consisting of a set of points, lines, and/or surfaces, and a set of rules, used to define the positions of points in space in either two or three dimensions.

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Evaluating map projection scale error

This is related to a previous question How to determine projection parameters when customizing a projection I posted. I am trying to quantitatively evaluate scale distortion associated with choosing ...
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310 views

Mapproxy transformation from Web Mercator to WGS84

I want to transform tiles defined in Web Mercator (EPSG:3857) to WGS84 (EPSG:4326) using Mapproxy. Unfortunately the resulting WGS84 map gets more and more distorted to the poles. Here is my ...
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390 views

The drawing of Thiessen/Voronoi polygon boundaries - are the bisecting lines truly perpendicular?

I am concerned with how QGIS (version 2.8.1) and ArcGIS (version 10.0) draw "perpendicular bisecting lines" when Thiessen/Voronoi polygons are created. When using either program to create these ...
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509 views

How to interpolate within defined boundaries of a deformed mesh using R?

My goal is to create an interpolation map of some output model results that are mapped on a deformed mesh (from a numerical simulation). The model results are in an x-y plane (representing coordinates)...
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71 views

Showing Polar coordinate grid?

I've found some maps for Antarctica https://nga.maps.arcgis.com/home/webmap/viewer.html How can I show polar coordinate grid for it? I've got the grid source code in grid_wgs.js (I use OpenSeaMap ...
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92 views

Adding GDA2020 NTv2 transformation to ArcGIS 10.5

The implementation of GDA2020 is drawing near! In an effort to be ready before time I have downloaded the NTv2 Grid Shift Binary (GSB) transformation grid from ISCM (available here) who are the ...
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184 views

Wrong reprojecting of a shapefile with to_crs in GeoPandas

When reprojecting an ESRI Shapefile (EPSG:21781) into an EPSG:4326 with QGIS and then importing the resulting file in GeoPandas and plotting it, the coordinates are correct. When importing the same ...
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273 views

Re-referencing raster in rotated coordinate system by “de-rotating” it

My Trying to define a "rotated regular grid" coordinate system in QGIS question about this got closed because there was already an answer to it, which I understand. I went to the answer in ...
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101 views

Automatically creating user CRS from postgis in QGIS

I have my custom CRS in table "spatial_ref_sys" in database. When I load layer from schema "public", QGIS create this CRS. But if layer from other schema, it's not. What I need to solve this problem?
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359 views

Fuller/Dymaxion in proj4/gdal/qgis?

I know this question has been asked a million times already, but I can't find many detailed responses on exactly what I want to do. As far as I can tell, the full C code for the fuller projection is ...
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79 views

Sphere rendering inside out using QGIS on Ubuntu?

I'm trying to use QGIS to show earthquakes around a 3d globe. I changed my CRS to 'Sphere_Van_der_Grinten_I' and it rendered like this: Here's a report from Hardinfo on my system and display: ...
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880 views

QGIS: CRS, ellipsoids and area calculation

I have a doubt about dynamic CRS, ellipsoids and area calculations. I am using QGIS 2.14.0 (still waiting for IT to install 2.14.11...) When I load a polygon table into a new, empty project, it comes ...
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425 views

Creating Proj4 string for local coordinates

I am fairly new to coordinate system conversion, so am rather lost on the following problem. We have been using Proj4 to convert between various coordinate systems which is fine for known coordinate ...
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815 views

Crop raster based on another raster R

library(raster) How can one clip one raster based on another raster? RasA: class : RasterLayer dimensions : 459, 533, 244647 (nrow, ncol, ncell) resolution : 10000, 10000 (x, y) extent ...
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Why does field calculator compute area in square meters?

I am using EPSG:102748, and have set my Settings/Option preferred measurement units to ft. My CRS is NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet, and when I use the measure tool, it returns ...
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623 views

Is there a way to expose Spherical Mercator Lat Lon in Google Map API?

The map tiles in the Google Maps are in Spherical Mercator projection (srid 900913), but in the API the methods report coordinates in Lat/Lon WGS84, e.g. map.getCenter(). Is there a way to return the ...
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Convert land-based camera image pixel x,y to ground lat/long or x,y,z

I have a number of cameras at various known locations (x,y,z) and directions that are above ground about 20 feet pointed at different ground locations about 100 feet away from each camera, and whose ...
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Fortifying re-projected shapefile for ggplot2 in R

I have a shapefile of US county boundaries which I got from the NHGIS. I can load the file using the rgdal package and see information about it: library(rgdal) shp_1860 <- readOGR("shp", "...
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835 views

Reprojecting raster data from a rotated pole grid

I have some raster data (ASCII grid files) that use a custom rotated-pole projection, that I'd like to reproject into something more useful, such as lon/lat WGS84. A description of the grid projection ...
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94 views

Proj.NET transform wkt to lat lon coordinate list

I am looking to transform from a WKT in 27700 into lat lon list of coordinates, but cannot quite work out how to do it using this library: https://archive.codeplex.com/?p=projnet I can easily do a ...
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48 views

Imported data shifted based on Google Maps

I am trying to import points from a shapefile in QGIS. First, I select the correct coordinate reference system (NAD83 / MTM zone 11) when importing the file, and it imports correctly. I even checked ...
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76 views

Intersection and area calculations in geographic vs. projected coordinates

I think one should do intersection calculations when layers are in the same coordinate system, and one should do area calculations in the appropriate projected coordinate system. The order matters, ...
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106 views

Finding correct CRS using QGIS?

I have a GeoTIFF layer (downloaded from US Dept of Interior) that is US population density. The metadata claims it is in EPSG:4267, which isn't even intended for use in that part of the world. (east ...
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107 views

Georeferencing image in QGIS?

I have a problem with projection. When I try to georeference an image in QGIS, I set up CRS WGS 84 Pseudo Mercator (EPSG: 3857). That info appears in georeference settings and it is also my default ...
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93 views

Local grids with rotated north in QGIS

Like many people in geology and archaeology I need to work with local grids that have eastings and northings from a specific reference point, and typically have a difference alignment/direction of ...
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65 views

create custom SRID from OGCWKT

I wanted to create a new SRID for use in PostGIS. My goal is to have a SRS that can cover an entire state (instead of have multiple zones as in SPCS). For example, I wanted to create a new SRS for ...
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47 views

Export/Import CRS for use on similar/same file?

I have a slightly strange request. I have access to a set of geo-ref'd PDFs that have multiple layers within the file. As touched on in other threads, there's no good way (at this time) to turn on/off ...
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107 views

Scaling two rasters to same elevation scale in QGIS?

I'm pretty new to using GIS, but I've got two overlapping rasters of the same general area - one's a 1m resolution DEM from the Pennsylvania side, and the other's a 0.6m DEM resolution from the ...
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225 views

Determining map-projected coordinates in custom CRS for Leaflet?

I have some static USA maps in Lambert Conformal projection that I would like to overlay in Leaflet together with geo-reference support. They are centered at 38N, 98W. I have found that the closest ...
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58 views

Different coordinate systems match in QGIS but not in ArcGIS

I have digitized some shapefiles (polygons) in QGIS. Some polygons have the CRS 5678 DHDN 3-Degree Gauss Kruger Zone 4 E-N and the rest have the CRS 4326 WGS84. The Project coordinate system is also ...
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449 views

How to get pixel coordinates in QGIS georeferenced output map?

using the QGIS Georeferencer GDAL plugin, I can select GCPs (ground control points) on a map (plain raster input map image in a format like PNG or TIF) in an unknown projection and boundaries, and ...
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38 views

Conic projection view transformation

I am building a custom map viewer, part of meteorological production system, using Java language and GeoTools library. I have prepared a custom map renderer, using OpenGL, that allows to display maps ...
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351 views

Can't get georeferenced Autocad DXF to right coordinates

I am not a frequent Autocad user. I wanted to export some floorplans from Autocad 2016 DWG to a final GeoJSON file to be loaded in a Google maps JS app. My steps are: 1)in Autocad set a location ...
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163 views

Can gdal be used to generate a single patch of the HEALPix projection?

Given a geo-referenced map of the world, I am able to produce a version with a HEALPix projection using gdalwarp like this: gdalwarp -t_srs '+proj=healpix +a=1 +ellps=WGS84 +wktext' -te -3.14159265 -...
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61 views

How to reproject a latlong J2000 coordinate image into latlong Galactic Coordinate image

I have a 2x1 ratio lat/long projection of the night sky in J2000 equatorial coordinates (the fixed equatorial coordinate system on Jan 1.5, 2000). I need to convert this into a 2x1 ratio lat/long ...
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0answers
2k views

Converting lat/long to EPSG:3857 coordinates

The map widget I'm using gives me click locations in lat/long. I need to convert those coordinates to EPSG:3857 to query a database. Most of the solutions I've found use the formula described in ...
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0answers
372 views

QGIS 3D Globe Plugin Elevation Map Projection

I'm trying to get a map setup using the QGIS 'Globe Plugin'. I've been trying to use the UK Environment Agency LIDAR data as an elevation map. After a bit of puzzling this out I've found that the ...
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0answers
494 views

Aligning layers in QGIS?

I am new at QGIS and am having a problem aligning layers. Possibly I just don't understand how projection works. I have two layers: GPS waypoints collected in a GPS UTM zone 55N Polygon shapefile ...
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0answers
549 views

Converting KML coordinates to Leaflet

I am trying to convert a Google Map KML file to a csv, to map the longitude and latitude points on Leaflet. But the coordinates keep mis-projecting and some end up off the land mass. The steps I have ...
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0answers
115 views

Rectangle shapefiles with the same extents does not align perfectly after projection

I have a rectangle shapefile built with UTM19 coordinates using a python script, and then projected to NAD83_CSRS (EPSG:4617). I have a second rectangle shapefile built with the same method (python ...
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0answers
184 views

Wrong area using Albers Equal Area Projection in GRASS for Java, Indonesia

I am just getting to know GRASS 7.0 and I am struggling finding a good projection to work on a spatial analysis of Java, Indonesia. I am new to the forum, so if information's are missing for a better ...
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0answers
706 views

Creating custom CRS based on local project parameters in QGIS?

I'm having trouble creating custom proj4 CRS files to work with existing .shp files on local project coordinates. (Local in that the coordinates are relative only to themselves and not the 'real world'...
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0answers
194 views

Regridding vector values

I'm trying to regrid and interpolate vector values from WAM model output. I got WAM model netCDF output in rotated grid, I need to interpolate it to another grid which is some variant of LAEA ...
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0answers
3k views

how to set the geotransform using GDAL in python

I am trying to create an image from a numpy array and georefenrece it so that I can import it into qgis. I have the latitude and longitude in degrees for the top left corner of the array as well as ...
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0answers
324 views

Which spatial-reference system is used by the Haversine formula?

I've been reading Pro Spatial with SQL Server 2012. It discusses the various spatial-reference systems (SRS) that can be used when defining a coordinate system. According to the book, Google uses ...
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228 views

Which projection can I use to see alignments on great circles?

I want to put on a QGIS map some historical sites to check if they are aligned. If an alignement exists, the points should stay on a great circle (is this correct?). I want to visually verify this ...
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0answers
859 views

Align vector and raster layers with D3

I have a geocoded raster image that I want to use as the background to a vector map with D3.js. The screenshot shows the layers in QGIS (grey is raster). Here's the markup for the map: <div class="...
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0answers
227 views

Finding centroids for icosahedral gnomonic projection?

I've been trying to create an icosahedral gnomonic projection, like this example by Jason Davies or this one (the Fisher projection). The method that I initially used was using the centroid of each ...
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0answers
82 views

How do I trick QGIS's map composer into chopping off the 000's in UTM coordinates?

In QGIS 2.8 (ubuntu), you can create a map with ticks and labels. I want the first two digits to be smaller sized, the next 3 to to be normal sized, and hide the last 3 digits. QGIS does not offer ...
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243 views

Error in Measuring distance using QGIS?

I am using the current Qgis 2.6.1 and having problems using the measuring distance function. The 'Measure Line' is giving me distances which is completely wrong and the scale shown was too big also. ...