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I have tried running the CSVtoPoint script in 4326 and 32651 project CRS but the results are the same.

I can just use the point layer in 4326 but it is not a projection so it uses degrees instead of meters which makes super big 10-meter buffers (what the bufferPoint2 script does). Reprojecting the 4326 point to 32651 works: aligns and produces the right buffer. But I want to know why this happens.

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When you import the CSV files with latitude and longitude in them - I'm assuming that means values like 51,2 (or other "small" values) - you commit the cardinal sin of lying to QGis about their projection. QGis is very trusting and believes you when you say these values are in metres measured from some distant origin. Thus you get incorrectly placed data (somewhere very close to that origin) and wrong distances.

So when you import the data you have to accept that it is stored in degrees and admit this to QGis. You then need to reproject the data to a projection that is in metres. If you are sure you live in EPSG:32651 then that is a good choice, to reproject your data you select the layer and export the layer to a new file (geopackage is a good choice here) with the new CRS you need (EPSG:32651) - QGis will then add this new file to your project as a new layer. This layer will be in metres and you can proceed accordingly.

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  • So, when I use DMS coordinates in my CSV file, QGIS assumes that the CRS is non-projected thus a Geographic Coordinate System?
    – BallpenMan
    Commented Feb 28, 2020 at 9:35
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    It's not an assumption, your data is not projected and is geographic - don't lie to QGIS about this
    – Ian Turton
    Commented Feb 28, 2020 at 10:20

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