Features placed 7.5 thousand kms off correct location using QGIS?

Question

I have been counting muskrat dens on lakes with aerial photos by creating a feature in a separate shapefile. I checked my progress after doing about 80 small lakes and suddenly, half of the lakes were off of their correct location (7.5 km south) and half of them are in the right spot.

I can't seem to remember, but I think that I wanted to confirm that the projection was correct and I confirmed the right projection of the layer.

Is it possible that this confirmation changed the first half of my layers and when I continued with the rest, they were placed correctly?

Is there anyway to reproject some of the features in a shapefile?

Answer 1

It does sounds like you have changed the CRS half through adding the features.

You can re-project those points by selecting them, then right click on the shapefile layer in the table of contents and select 'Save selection as'.

You can then choose to re-project those features to 'Selected CRS' and choose the appropriate CRS from the list.

Finally you will want to merge your exported Shapefile (now with correct CRS) with the original Shapefile (you will also need to delete the incorrect features before merging). This can be done using the 'Merge Shapefiles to one' tool found in the 'Vector' > 'Data management tools' menu.