> 1. vikdemlayer.c:620
>
>Here the code makes sure that array index is not out of bounds, but it seems
>that the condition should be 'if(new < 0)' rather than 'if(new < 1)'. '1' is a
>valid array index.
Agreed (I think you mean '0' is a valid array index).
Thus I also think instead of using
prevcolumn = g_ptr_array_index ( dem->columns, x+1);
explicitly use 0, so its:
prevcolumn = g_ptr_array_index ( dem->columns, 0 );
Similarly the upper bound should be explicit, so in a few lines further down,
instead of:
nextcolumn = g_ptr_array_index ( dem->columns, x-1);
it should be:
nextcolumn = g_ptr_array_index ( dem->columns, dem->n_columns-1);
Note that having tried this (as in fixing it to use column 0) there appears to
be little difference in the end results.
Further note that this is only for the DEM gradient drawing in getting a colour
by checking the change in elevation values.
Currently the code suffers from a small edge effect for drawing each DEM file,
as in working out the colour it only uses the current DEM file; as opposed to
attempting to get values from the neighbouring DEMs (i.e. the elev at a
location outside this DEM) to calculate the gradient across the boundary.
Depending on how simple this is to fix or if computationally significant, I'll
at least put a comment in the code about it.
>2. vikdemlayer.c:787
>Here the code draws DEM in UTM mode and is again checking column index, and I
>think that it again is making a mistake. The 'x > 0' condition probably should
>be replaced with 'x >= 0', because '0' is still a valid array index.
Agreed it should be 'x >= 0'.
Note this is not quite 'drawing DEM in UTM mode', this is for drawing when the
DEM data files themselves are in UTM format (as opposed to setting Viking to
draw in UTM mode). However such DEM files are only available if you have
configured viking compiling with '--enable-dem24k' and then using a separate
program 'sdts2dem' - basically some fairly obscure USGS Topo files, that I
doubt hardly anyone uses with viking.
Indeed having never tried it before, I run the perl script (that Viking would
invoke) to acquire such DEM files but the website it accesses: "geocomm.com"
doesn't exist anymore.
As ever, thank you for taking the time to analyze and commit on the Viking code.
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