Here are some examples of using
stilts tgridmap in=ravedr4.fits coords=HRV nbins=20
ravedr4.fits. The output is a table with columns
HRV, giving the central value of each bin, and
COUNT, giving the number of input rows with HRV values in that bin; additional columns
HRV_higive the lower and upper bounds of the bin. The bin size is determined from the actual range of the HRV values in the input table, combined with the requested bin count of 20; however, the bin size will be chosen as some round number, so the bin count (number of rows in the output table) may not be exactly as requested.
stilts tgridmap in=ravedr4.fits coords=HRV binsizes=100 bounds=-450:450 sparse=false
sparse=falseparameter means that rows will be output for all 9 bins, even if some of them are empty. Note supplying bin geometry in this way allows control of bin boundaries; in this case HRV=0 is in the middle of a bin not at a bin boundary. This will also be faster, since no initial scan to determine actual data ranges has to be performed.
stilts tgridmap in=edr3-local.fits icmd='addcol nobs astrometric_n_good_obs_al' icmd='addcol g_abs phot_g_mean_mag+5*log10(parallax*0.01)' coords='bp_rp g_abs' binsizes='0.125 0.5' bounds='-1:6 -5:20' cols='1;count;NUM nobs;sum;SUM_NOBS nobs;mean;MEAN_NOBS' out=grid-stats.vot sparse=false
g_abscoordinate values for each grid point, as well as columns NUM containing source density, and columns SUM_NOBS and MEAN_NOBS containing respectively the sum and mean of the
nobscolumn in each grid cell. Since
sparse=falsethe number and arrangement of output rows is determined by the binsizes and bounds (57*51 rows) independent of the input data, and could be compared with similar runs on different input tables. The
icmd=addcol...parameters prepare values for accumulation ahead of the actual gridding step for convenience though this isn't essential, the relevant expressions could be used directly in the
colsparameters if preferred.