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4

You first need to decide what distortion properties would you like to control for. That is to say, are you interested in preserving area, distance or shape? There is a decision support tool for selecting projections that is quite user friendly and available for free from Oregon State University (Map Projection Selection Tool). Note that you can select the ...


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You can use some projections that are provided by ESRI, depending on whether distance or area is important for you. They look very similar: ESRI:102032 South_America_Equidistant_Conic +proj=eqdc +lat_0=-32 +lon_0=-60 +lat_1=-5 +lat_2=-42 +x_0=0 +y_0=0 +ellps=aust_SA +units=m +no_defs ESRI:102033 South_America_Albers_Equal_Area_Conic +proj=aea ...


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WGS 84 is not a cartesian coordinate system. You can use it directly for your visualisation purposes, but you should be aware that distances, shapes and areas will be distorted. If you want to project your WGS 84 coordinates to a 2D cartesian reference system, you'll need to choose a destination coordinate system : there is no single answer to your ...


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follow the instructions I gave here How to reproject a vector layer in QGIS? and you are done: before: and after:


3

I tried this out and had no issues... once the data was re-projected and added to the map, I re-set the map to EPSG:3857, added the Google map via OpenLayers, and the re-projected (and projected on the fly) dataset of yours worked just fine:


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You can solve the geodesic intersection problem using the ellipsoidal gnomonic projection. The method is described in §8 of my paper, Algorithms for geodesics, and code to implement the solution using GeographicLib is available here


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Ok finally I found the solution with postGIS st_translate select id, st_translate(geom, -0.00045, -0.00073) from tmp_che_adm3 The most important part is to find the correct offset in degrees. I think, for simply move geometries in XY is faster than qgsaffine


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Since all the other countries seem to match, the problem seems to be with the swisserland data. Check again if u have set the right coordinate system for the layer. If it checks out, its probably a faulty dataset. If u know the offset, you could try to reproject the layer with the qgsaffine plugin. Martin Update on how to use it: -Install the plugin, you ...


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In QGIS 2.4 (not sure about previous versions), when you right-click on the layer and choose "Save As...". On the "Save vector layer as..." dialog, be sure to change the CRS dropdown from "Layer CRS" to "Selected CRS" and then browse to "WGS 84 / Pseudo Mercator (EPSG: 3857)". Everything else should work the same and give you the output you expect.


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The Define Projection tool only changes the associated projection, it does not modify the geometry of the feature or shapefile. (Useful if you get data with no associated projection. Not useful if you're trying to transform to a different coordinate system.) Since you ran this before running Project (which mathematically transforms the data into a different ...


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Quoted from About coordinate systems and map projections Other projections minimize overall distortion but don't preserve any of the four spatial properties of area, shape, distance, and direction. The Robinson projection, for example, is neither equal area nor conformal but is aesthetically pleasing and useful for general mapping. You may want ...


3

Yes, you are right. Finnish nautical maps printed 2002 or before are all based on KKJ coordinated system. KKJ coordinates may differ from GPS-coordinates (WGS84) as much as 200 meters. Starting from 2003 have all new nautical charts been published in EUREF-FIN (appr. WGS 84). These new nautical charts apply international INT chart symbols. Because shallow ...


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I've used this online converter successfully: http://converter.mygeodata.eu/vector



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