3

I have ranges of x and y coordinates in EPSG:102002 GRS 80 that I need to convert into EPSG:4326 WGS 84. I have tried different suggestions here and here but nothing has worked so far.

I find myself manually converting points of x and y coordinates to lat and lon coordinates online, one point at a time (N = 8200).

Is there a way to automatize this process where it also takes the projection into consideration?

I am pretty flexible with the program using, as long as it is not ArcGIS and Java.

Here is a sample

x             y            lat       lon
-3145588.03  5018975.86   63.30     177.62
-3115010.95  5010633.39   63.55     177.94
-3084474.59  5002315.52   63.80     178.28
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    EPSG:102002 does not exist. Do you mean the ESRI projection 102002 that converts into Proj string +proj=lcc +lat_0=40 +lon_0=-96 +lat_1=50 +lat_2=70 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs? Edit: QGIS seems to use EPSG as a synonyme. – user30184 Nov 29 '20 at 10:00
  • Y coordinates in the sample should be positive, 5018975.86, not -5018975.86. – user30184 Nov 29 '20 at 10:03
  • @user30184, yes. EPSG: 102002 - Canada Lambert Conformal Conic. – Thomas Nov 29 '20 at 10:04
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    Ok, QGIS is then doing something by its own. EPSG does not know such coordinate system epsg.org/search/…. – user30184 Nov 29 '20 at 10:06
6

You can use QGIS:

  1. Add delimited text layer enter image description here
  2. Reproject Layer enter image description here
  3. Add geometry attributes enter image description here enter image description here
4

To include varying projections in the transformation to lat/lon (EPSG:4326), you can use a variable for the current EPSG of your source, so than you don't have to care about which EPSG your data is in, see here: Getting lat/long for centroids using QGIS

You can use this directly in the field calculator, adapting the expression as follows, whereas "x" and "y" are the fieldnames for your original coordinates. This expression works whatever CRS you have for your input (this is for lat; replace the y at the beginning with x for lon):

y (
   transform (
      ( make_point ( "x" , "y" ) ) ,
      @project_crs , 
      'EPSG:4326'
   )
)

qgis field calculator expression to add latitude longitude coordinates

To import your original points, save the coordinates in a simple csv (pasting them in a text editor would do the job) and import them to QGIS as delimited text, selecting the CRS:

qgis import csv delimited text as points layer

0

As @BERA suggested you can reproject the layer. You could also create a new field with the field calculator using the to_dms() function. As suggested here

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