[GRASS-user] Re: weird results with mapcalc on different region extents

maning sambale emmanuel.sambale at gmail.com
Thu Mar 11 06:10:28 EST 2010 

same issue with grass6.4 in Ubuntu,
runs OK with small region but not in a bigger region


On Thu, Mar 11, 2010 at 3:05 PM, maning sambale
<emmanuel.sambale at gmail.com> wrote:
> Hi,
>
> I have this simple mapcalc run that determines the proportion of
> landcover type over the land, given a moving window.
>
> A = binary map 1=with cover pixels, 0=w/o cover pixels
> B = binary map 1=land pixels 0=non-land pixels
> WINDOW = 5
>
> r.neighbors input=A output=C method=sum size="$WINDOW" --o
> r.neighbors input=B output=D method=sum size="$WINDOW" --o
>
> r.mapcalc << EOF
> E = 1.0 * C
> F = 1.0 * D
> pf = (E/D)
> EOF
>
> pf should result in a percentage of cover pixels over the land.
>
> If I run the data in a small region and the results are OK.
> r.info -r pf
> min=0
> max=1
>
> r.stats -acp pf
>  100%
> 0-0.003922 83506029.482130 102816  26.75%
> 0.039216-0.043137 1436762.431469 1769   0.46%
> 0.047059-0.05098 1624.378102 2   0.00%
> 0.066667-0.070588 2436.567153 3   0.00%
> 0.078431-0.082353 916149.249687 1128   0.29%
> 0.098039-0.101961 812.189051 1   0.00%
> 0.117647-0.121569 987621.886188 1216   0.32%
> 0.14902-0.152941 812.189051 1   0.00%
> 0.156863-0.160784 724472.633618 892   0.23%
> 0.2-0.203922 990058.453341 1219   0.32%
> 0.239216-0.243137 842240.046034 1037   0.27%
> 0.247059-0.25098 1624.378102 2   0.00%
> 0.266667-0.270588 2436.567153 3   0.00%
> 0.278431-0.282353 616451.489816 759   0.20%
> 0.298039-0.301961 1624.378102 2   0.00%
> 0.317647-0.321569 604268.654049 744   0.19%
> 0.333333-0.337255 1624.378102 2   0.00%
> 0.356863-0.360784 660309.698578 813   0.21%
> 0.4-0.403922 1019297.259182 1255   0.33%
> 0.439216-0.443137 621324.624123 765   0.20%
> 0.447059-0.45098 1624.378102 2   0.00%
> 0.466667-0.470588 1624.378102 2   0.00%
> 0.478431-0.482353 614827.111714 757   0.20%
> 0.498039-0.501961 1624.378102 2   0.00%
> 0.517647-0.521569 594522.385435 732   0.19%
> 0.533333-0.537255 1624.378102 2   0.00%
> 0.556863-0.560784 645690.295657 795   0.21%
> 0.6-0.603922 1009550.990569 1243   0.32%
> 0.639216-0.643137 631883.081788 778   0.20%
> 0.647059-0.65098 2436.567153 3   0.00%
> 0.666667-0.670588 1624.378102 2   0.00%
> 0.678431-0.682353 644878.106606 794   0.21%
> 0.698039-0.701961 3248.756205 4   0.00%
> 0.717647-0.721569 605080.843100 745   0.19%
> 0.733333-0.737255 1624.378102 2   0.00%
> 0.74902-0.752941 812.189051 1   0.00%
> 0.756863-0.760784 808940.294937 996   0.26%
> 0.8-0.803922 1011175.368671 1245   0.32%
> 0.839216-0.843137 745589.548948 918   0.24%
> 0.847059-0.85098 3248.756205 4   0.00%
> 0.866667-0.870588 4873.134307 6   0.00%
> 0.878431-0.882353 998180.343853 1229   0.32%
> 0.898039-0.901961 1624.378102 2   0.00%
> 0.917647-0.921569 933205.219761 1149   0.30%
> 0.933333-0.937255 8121.890511 10   0.00%
> 0.94902-0.952941 8934.079563 11   0.00%
> 0.956863-0.960784 1423767.406651 1753   0.46%
> 0.996078-1 93443162.522784 115051  29.94%
> * 115074193.521699 141684  36.87%
>
> But, when I run the data in the full map region, I get a different result
>
> r.info -r pf
> min=0
> max=25
> r.stats -acp pf
>  100%
> 0-0.098039 1593170550.199143 1961576  39.19%
> 0.098039-0.196078 18625931.509825 22933   0.46%
> 0.196078-0.294118 26394519.783980 32498   0.65%
> 0.294118-0.392157 13855133.023422 17059   0.34%
> 0.392157-0.490196 24355925.265619 29988   0.60%
> 0.490196-0.588235 13444165.363544 16553   0.33%
> 0.588235-0.686275 24779075.761263 30509   0.61%
> 0.686275-0.784314 15370677.792853 18925   0.38%
> 0.784314-0.882353 29887744.892934 36799   0.74%
> 0.882353-0.980392 25306186.455453 31158   0.62%
> 0.980392-1.078431 1858477789.081065 2288233  45.71%
> 1.078431-1.176471 77970.148910 96   0.00%
> 1.176471-1.27451 51980.099273 64   0.00%
> 1.27451-1.372549 25177.860585 31   0.00%
> 1.372549-1.470588 21116.915330 26   0.00%
> 1.470588-1.568627 28426.616790 35   0.00%
> 1.568627-1.666667 5685.323358 7   0.00%
> 1.666667-1.764706 14619.402921 18   0.00%
> 1.764706-1.862745 17055.970074 21   0.00%
> 1.862745-1.960784 14619.402921 18   0.00%
> 1.960784-2.058824 4873.134307 6   0.00%
> 2.058824-2.156863 14619.402921 18   0.00%
> 2.156863-2.254902 5685.323358 7   0.00%
> 2.254902-2.352941 11370.646716 14   0.00%
> 2.352941-2.45098 1624.378102 2   0.00%
> 2.45098-2.54902 11370.646716 14   0.00%
> 2.54902-2.647059 3248.756205 4   0.00%
> 2.647059-2.745098 2436.567153 3   0.00%
> 2.745098-2.843137 12995.024818 16   0.00%
> 2.843137-2.941176 812.189051 1   0.00%
> 2.941176-3.039216 7309.701460 9   0.00%
> 3.039216-3.137255 10558.457665 13   0.00%
> 3.137255-3.235294 812.189051 1   0.00%
> 3.235294-3.333333 812.189051 1   0.00%
> 3.333333-3.431373 4060.945256 5   0.00%
> 3.431373-3.529412 812.189051 1   0.00%
> 3.529412-3.627451 8934.079563 11   0.00%
> 3.627451-3.72549 1624.378102 2   0.00%
> 3.72549-3.823529 1624.378102 2   0.00%
> 3.823529-3.921569 812.189051 1   0.00%
> 3.921569-4.019608 3248.756205 4   0.00%
> 4.117647-4.215686 10558.457665 13   0.00%
> 4.313725-4.411765 812.189051 1   0.00%
> 4.411765-4.509804 812.189051 1   0.00%
> 4.509804-4.607843 812.189051 1   0.00%
> 4.607843-4.705882 812.189051 1   0.00%
> 5-5.098039 20304.726279 25   0.00%
> 5.196078-5.294118 812.189051 1   0.00%
> 5.294118-5.392157 2436.567153 3   0.00%
> 5.980392-6.078431 5685.323358 7   0.00%
> 6.176471-6.27451 12995.024818 16   0.00%
> 6.27451-6.372549 812.189051 1   0.00%
> 6.666667-6.764706 812.189051 1   0.00%
> 6.960784-7.058824 1624.378102 2   0.00%
> 7.254902-7.352941 812.189051 1   0.00%
> 7.45098-7.54902 812.189051 1   0.00%
> 7.647059-7.745098 812.189051 1   0.00%
> 7.941176-8.039216 3248.756205 4   0.00%
> 8.333333-8.431373 13807.213869 17   0.00%
> 8.921569-9.019608 2436.567153 3   0.00%
> 9.411765-9.509804 812.189051 1   0.00%
> 10-10.098039 3248.756205 4   0.00%
> 10.490196-10.588235 2436.567153 3   0.00%
> 10.980392-11.078431 2436.567153 3   0.00%
> 11.960784-12.058824 2436.567153 3   0.00%
> 12.45098-12.54902 10558.457665 13   0.00%
> 12.941176-13.039216 1624.378102 2   0.00%
> 13.921569-14.019608 812.189051 1   0.00%
> 15-15.098039 1624.378102 2   0.00%
> 15.980392-16.078431 1624.378102 2   0.00%
> 16.960784-17.058824 1624.378102 2   0.00%
> 18.921569-19.019608 1624.378102 2   0.00%
> 20-20.098039 1624.378102 2   0.00%
> 22.941176-23.039216 4873.134307 6   0.00%
> 23.921569-24.019608 7309.701460 9   0.00%
> 24.901961-25 14619.402921 18   0.00%
> * 421552919.784229 519033  10.37%
>
> The range of values are not in percentage anymore (0-25).
>
> Any ideas?  Using GRASS 6.4.0RC5 from Kingchaos binaries.
>
> Thanks!
> --
> cheers,
> maning
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> ------------------------------------------------------
>



-- 
cheers,
maning
------------------------------------------------------
"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/
------------------------------------------------------

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