[R-sig-Geo] How to interpolate river cross section with R?

[Stephen Sefick]

I think I would look into GRASS GIS.  There are some very good 
interpolation algorithms that are implemented there already.  Likely, 
you can do this with either R or GRASS, whether it is sensible is up to 
you.

It sounds like the survey data and the DEM data are referenced to 
different elevation datums.  How far off are the elevation values?

On Sat 10 Dec 2011 08:24:38 AM CST, Wongwatana Sombunying wrote:
> Dear all
>
>            I have two data elevation sources which are DEM grid file and
> river cross-section surveyed data. DEM data is grid file covering the whole
> watershed area. Surveying data is 500-m interval cross sections along a
> river reach in the watershed area. However, these are much difference in
> elevation value at the same coordinate points. I want to generate a new
> grid file from surveyed data along the river reach to be input of
> hydrodynamic model.  Can I solve this problem with any R packages?  or  Can
> I use R to  interpolate river cross section between upstream and downstream
> river cross sections?
>
> The example of 2 cross section data are as following :
>
> Cross section No- 1
> chainage,x,y,z
> 0,537545.1,2219340,452.11
> 4,537541.1,2219340,452.05
> 12,537533.2,2219339,451.54
> 14,537531.2,2219338,451.6
> 16,537529.2,2219338,451.39
> 24,537521.3,2219337,450.13
> 34,537511.4,2219336,450.32
> 39,537506.5,2219335,448.55
> 44,537501.5,2219334,447.05
> 49,537496.6,2219333,446.15
> 54,537491.6,2219333,445.58
> 59,537486.7,2219332,445.11
> 64,537481.7,2219331,445
> 69,537476.8,2219331,444.83
> 74,537471.8,2219330,444.94
> 79,537466.9,2219329,444.69
> 84,537461.9,2219329,444.76
> 89,537456.9,2219328,444.8
> 94,537452,2219327,444.94
> 99,537447,2219326,445.04
> 104,537442.1,2219326,445.94
> 110,537436.2,2219325,446.89
> 114,537432.2,2219324,450.51
> 124,537422.3,2219323,457.19
> 134,537412.4,2219322,464.5
> 144,537402.5,2219320,471.79
> 154,537392.6,2219319,478.5
>
> Cross section No- 2
>
> chainage,x,y,z
> 0,537545.1,2219340,452.11
> 4,537541.1,2219340,452.05
> 12,537533.2,2219339,451.54
> 14,537531.2,2219338,451.6
> 16,537529.2,2219338,451.39
> 24,537521.3,2219337,450.13
> 34,537511.4,2219336,450.32
> 39,537506.5,2219335,448.55
> 44,537501.5,2219334,447.05
> 49,537496.6,2219333,446.15
> 54,537491.6,2219333,445.58
> 59,537486.7,2219332,445.11
> 64,537481.7,2219331,445
> 69,537476.8,2219331,444.83
> 74,537471.8,2219330,444.94
> 79,537466.9,2219329,444.69
> 84,537461.9,2219329,444.76
> 89,537456.9,2219328,444.8
> 94,537452,2219327,444.94
> 99,537447,2219326,445.04
> 104,537442.1,2219326,445.94
> 110,537436.2,2219325,446.89
> 114,537432.2,2219324,450.51
> 124,537422.3,2219323,457.19
> 134,537412.4,2219322,464.5
> 144,537402.5,2219320,471.79
> 154,537392.6,2219319,478.5
>
>      Thank you for your help.
>

-- 
Stephen Sefick
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