[ncl-talk] interpolating irregular data to regular lat-lon grid

[Tabish Ansari]

Hi

I have got emissions data at 1km resolution as a text file. They were
derived from high resolution shapefile polygons. The emissions value for
each polygon was assigned to the lat/lon of the centroid of each polygon.
Naturally, these centroids do not occur at equal lat/lon spacing.
Currently, my data looks like this:

LON LAT CO NOX SO2 NMVOC NH3 BC PM25 PM10
 -11.5746   48.3209    0.0001    0.0009    0.0000    0.0000    0.0000
 0.0000    0.0000    0.0000
 -11.5655   48.3198    0.0081    0.0857    0.0004    0.0031    0.0000
 0.0005    0.0015    0.0016
 -11.5530   48.3183    0.0213    0.2257    0.0011    0.0080    0.0000
 0.0013    0.0040    0.0043
 -11.5402   48.3177    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -11.5267   48.3181    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -11.5133   48.3185    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -11.4998   48.3189    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4445   48.0253    0.0065    0.0686    0.0003    0.0024    0.0000
 0.0004    0.0012    0.0013
 -10.4394   48.0247    0.0031    0.0330    0.0002    0.0012    0.0000
 0.0002    0.0006    0.0006
 -10.4699   48.0345    0.0017    0.0178    0.0001    0.0006    0.0000
 0.0001    0.0003    0.0003
 -10.4600   48.0327    0.0166    0.1766    0.0009    0.0063    0.0000
 0.0010    0.0031    0.0034
 -10.4477   48.0314    0.0280    0.2971    0.0015    0.0106    0.0000
 0.0018    0.0053    0.0057
 -10.4386   48.0320    0.0100    0.1064    0.0005    0.0038    0.0000
 0.0006    0.0019    0.0020
 -10.4953   48.0438    0.0000    0.0000    0.0000    0.0000    0.0000
 0.0000    0.0000    0.0000
 -10.4863   48.0421    0.0092    0.0976    0.0005    0.0035    0.0000
 0.0006    0.0017    0.0019
 -10.4745   48.0401    0.0253    0.2689    0.0013    0.0096    0.0000
 0.0016    0.0048    0.0051
 -10.4615   48.0400    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4482   48.0403    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4376   48.0408    0.0159    0.1690    0.0008    0.0060    0.0000
 0.0010    0.0030    0.0032
 -10.5117   48.0513    0.0032    0.0339    0.0002    0.0012    0.0000
 0.0002    0.0006    0.0006
 -10.5012   48.0493    0.0196    0.2077    0.0010    0.0074    0.0000
 0.0012    0.0037    0.0040
 -10.4888   48.0484    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4754   48.0487    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4620   48.0490    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4486   48.0493    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4367   48.0498    0.0218    0.2315    0.0011    0.0083    0.0000
 0.0014    0.0041    0.0044
 -10.5371   48.0605    0.0003    0.0031    0.0000    0.0001    0.0000
 0.0000    0.0001    0.0001
 -10.5279   48.0588    0.0121    0.1287    0.0006    0.0046    0.0000
 0.0008    0.0023    0.0025
 -10.5158   48.0570    0.0268    0.2839    0.0014    0.0101    0.0000
 0.0017    0.0051    0.0054
 -10.5026   48.0571    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4892   48.0574    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057
 -10.4758   48.0577    0.0282    0.2991    0.0015    0.0107    0.0000
 0.0018    0.0053    0.0057


Is there a way to interpolate this data to a regular grid using NCL?

Thanks

Tabish


*Tabish U Ansari*

*Postdoctoral Researcher *

*Centre for Climate and Air Pollution Studies (C-CAPS)*
*School of Physics, NUI-Galway**, Ireland*
*ResearchGate: https://www.researchgate.net/profile/Tabish_Ansari
<https://www.researchgate.net/profile/Tabish_Ansari>*
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