New answers tagged utm
You can import your locations into QGIS/ArcMap/MapInfo or a spatialite/postgis database using the SIRGAS2000 (UTM 21s) coordinates. Then reproject the data to WGS84 and export the coordinates and location ids into a format that your database will import such as csv.
Googling this returns many informative pages. Here's one: http://www.uwgb.edu/dutchs/usefuldata/utmformulas.htm
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