Markus Neteler via RT wrote:
https://intevation.de/rt/webrt?serial_num=1977
> When using the d.histogram feature on a floating point raster such
> as elevations, the resulting axis tic marks and labels are often
> illegible.
>
> Workaround: Greatly reducing the number of bins (nsteps) in the
> histogram will produce resonable axes tic marks.
>
> Axes labels and tic marks should handle large numbers of bins
> gracefully.
It would be really good to get the horizontal ticks/labels problem
fixed. Is there anyone who is willing to take a look? I tried a while
but didn't find a solution (maybe it isn't that hard, though).
from previous attempt at fixing this bug:
==============================================
From: Hamish
Subject: Re: d.histogram label bug
Date: Wed, 5 Apr 2006 13:01:34 +1200
To: Markus
you will probably know the attached d.histogram label
bug (see screenshot).
yes
It seems to be "just" the density of tics/labels
which isn't estimated correctly (maybe divide by 10
or so to make it readable).
The raster map stats are:
n: 1116427
minimum: -23.1376
maximum: -8.79618
range: 14.3414
mean: -16.509
standard deviation: 2.02468
variance: 4.09934
variation coefficient: -12.2641 %
sum: -18431148.6160733774
AFAICT it only happens with FP maps, and if you stretch the window
larger or smaller it can fix itself.
I have tried a while but don't really understand
how it works in bar.c.
Maybe you could take a few minutes to investigate?
It's a bit complicated...
default for fs maps is to reduce to 255 cats as in r.stats, but the
calculation for tick spacing is using the FP range: conflict of units.
As proof of concept this fixes the ticks (I think, not a proper fix),
but the labels need changing too, as now they won't match up.
bar.c line ~120
// while((range_dmax - range_dmin)/tics[i].every > max_tics)
while ((num_cats/tics[i].every) > max_tics)
i++;
but I'm not sure if ticks should line up with the 255 rectangles or line
up with whole numbers of the FP range.
anyway, some why. Maybe I will look into it further once I have my next
batch of models running.
Hamish