Assuming you don't need a true, database-style auto-incrementing field (which would only work in PostGIS or Spatialite or another db data format), you could simply add a calculation step to your model, calculating an ID column with the expression:
$rownum
… this will give a unique, incremented set of integer values.
You can either reproject your polygon shapefile OR your dataset. EPSG is a short code for spatial projections. EPSG:4326 is the code for non-projected data in degrees using wgs84: http://spatialreference.org/ref/epsg/4326/
Reproject your polygon into 4326
france_wgs84 <- spTransform(france_L93, CRS("+init=epsg:4326"))
Reproject your dataset into Lambert93
data <- structure(list(centerid = c("0121H1", "0121H2", "0218H3", "0303H1",
"0303H2"), latitude = c(46.2236804, 46.2236804, 49.3700842, 46.3429172,
46.3429172), longitude = c(5.2108193, 5.2108193, 3.335127, 2.6089958,
2.6089958), adresse_complete = c("900 Route de Paris, 01440 Viriat, France",
"900 Route de Paris, 01440 Viriat, France", "46 Avenue du Général de Gaulle, 02200 Soissons, France",
"18 Avenue du 8 Mai 1945, 03100 Montluçon, France", "18 Avenue du 8 Mai 1945, 03100 Montluçon, France"
)), .Names = c("centerid", "latitude", "longitude", "adresse_complete"
), row.names = c(NA, 5L), class = "data.frame")
coordinates(data) <- ~longitude+latitude
proj4string(data) <- "+init=epsg:4326"
data_L93 <- spTransform(data, CRS("+proj=lcc +lat_1=44 +lat_2=49 +lat_0=46.5 +lon_0=3 +x_0=700000 +y_0=6600000 +ellps=GRS80 +units=m
+no_defs"))
Best Answer
First, save the layer as WGS84 and import it again. Then in the field calculator you can use $x or $y as a variable to get the x and y.
This was added in 1.7.