Talking
With Maps
  2010

            Imaging of geochemical data
               by interpolation within
               ge...
Talking
With Maps            Acknowledgements
  2010
            This work is based on research using a
            VB.Net...
Talking    Northern Ireland
With Maps
  2010




            Area: 14,000km2
Tellus Project: Northern Ireland
 Talking
With Maps              Soil data
  2010
Talking    Who uses Tellus data?
With Maps
  2010
            •   Environmental Agencies
            •   Commercial Indust...
Talking
                Potentially Harmful Elements (PHE)
With Maps                Nickel (Ni) in soils
  2010




      ...
Gridding by Inverse Distance
 Talking
With Maps
            Weighting: Chromium
  2010
Talking    Simplified Bedrock Geology Map
With Maps
  2010
Talking
With Maps
  2010      Methodologies

                 Inverse Distance Weighting

                            vers...
Talking    Bedrock geology
With Maps
  2010
            boundaries




                              Superficial geology
 ...
Talking
With Maps
  2010
Talking
With Maps
  2010
Talking
With Maps
  2010
Talking
With Maps
  2010
Talking
With Maps
  2010
4+4+4+3+2=17
 Talking    17/5=3.4
With Maps
  2010



                       3       4


                           4     ...
1-2.9
            4+4+4+3+2=17
                           3-4.9
 Talking    17/5=3.4       5-6.9
                         ...
1-2.9
            4+4+4+3+2=17
                           3-4.9
 Talking    17/5=3.4       5-6.9
                         ...
Talking
With Maps
  2010




            Step 1: Geology polygons are intersected with the 1km Grid
            Step 2: Ce...
Talking    Sample points
With Maps   and centroids
  2010
            (Parent material
            method )




          ...
Chromium in soils
 Talking
With Maps
  2010      New Parent
            Material mapping




            Old method using
...
Parent Material soil chemistry maps:
 Talking              optimum number of samples for Parent
With Maps
  2010
         ...
Evaluation of Parent Material and IDW
 Talking
              soil chemistry mapping using holdout
With Maps
  2010        ...
Chromium in
 Talking
            soils – all NI
With Maps
  2010
            New regional
            Parent
            M...
Nickel above Soil Guideline Values (SGV)
 Talking    Residential 130 mg/kg; Allotments 230 mg/kg
With Maps
  2010
Arsenic above Soil Guideline Values
 Talking    Residential 32 mg/kg; Allotments 43 mg/kg
With Maps
  2010
Talking
With Maps
  2010


            For more information
            Contact GSNI: gsni@detini.gov.uk

            GeoI...
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Imaging of geochemical data, by BGS NI

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Imaging of geochemical data, by BGS NI

  1. 1. Talking With Maps 2010 Imaging of geochemical data by interpolation within geological boundaries Don Appleton (British Geological Survey) Presented by Claire McGinn (Geological Survey of Northern Ireland)
  2. 2. Talking With Maps Acknowledgements 2010 This work is based on research using a VB.Net tool compiled for ArcGIS 9.3 by Keith Adlam (BGS) Data for this work were provided by the Tellus Project, funded by the Department of Enterprise, Trade and Investment of Northern Ireland. The contributions of GSNI and BGS staff who collected, prepared and analysed the Tellus soil samples is gratefully acknowledged.
  3. 3. Talking Northern Ireland With Maps 2010 Area: 14,000km2
  4. 4. Tellus Project: Northern Ireland Talking With Maps Soil data 2010
  5. 5. Talking Who uses Tellus data? With Maps 2010 • Environmental Agencies • Commercial Industries • Marine Scientists • Agricultural Departments • Universities • Local Councils • Regulatory Authorities
  6. 6. Talking Potentially Harmful Elements (PHE) With Maps Nickel (Ni) in soils 2010 • Arsenic (As) • Cadmium (Cd) • Chromium (Cr) • Lead (Pb)
  7. 7. Gridding by Inverse Distance Talking With Maps Weighting: Chromium 2010
  8. 8. Talking Simplified Bedrock Geology Map With Maps 2010
  9. 9. Talking With Maps 2010 Methodologies Inverse Distance Weighting versus Soil Parent Material (i.e. within geological boundaries)
  10. 10. Talking Bedrock geology With Maps 2010 boundaries Superficial geology boundaries
  11. 11. Talking With Maps 2010
  12. 12. Talking With Maps 2010
  13. 13. Talking With Maps 2010
  14. 14. Talking With Maps 2010
  15. 15. Talking With Maps 2010
  16. 16. 4+4+4+3+2=17 Talking 17/5=3.4 With Maps 2010 3 4 4 4 2 3 2 4 2 3 4+3+3+2+2=14 14/5=2.8
  17. 17. 1-2.9 4+4+4+3+2=17 3-4.9 Talking 17/5=3.4 5-6.9 7-8.9 With Maps 2010 4+3+3+2+2=14 14/5=2.8
  18. 18. 1-2.9 4+4+4+3+2=17 3-4.9 Talking 17/5=3.4 5-6.9 7-8.9 With Maps 2010 4+3+3+2+2=14 14/5=2.8
  19. 19. Talking With Maps 2010 Step 1: Geology polygons are intersected with the 1km Grid Step 2: Centroids are created for each geological polygon within each 1km polygon Step 3: VB.Net Tool identifies the nearest 5 soil sites to the centroid for the Parent material and superficial geology
  20. 20. Talking Sample points With Maps and centroids 2010 (Parent material method ) Rasterised image of the centroids interpolated within parent material boundaries
  21. 21. Chromium in soils Talking With Maps 2010 New Parent Material mapping Old method using IDW mapping.
  22. 22. Parent Material soil chemistry maps: Talking optimum number of samples for Parent With Maps 2010 Material mapping 2 1 n MSD = ∑ (estimated − measured ) n i =1   1.8 As AV 1.6 Cr AV Ni AV 1.4 Pb AV Average of As, Cr, Ni, Pb AV Overall average ALR-GALA 1.2 1 MSD 0.8 0.6 0.4 0.2 0 0 5 10 15 20 25 Number of neighbouring samples
  23. 23. Evaluation of Parent Material and IDW Talking soil chemistry mapping using holdout With Maps 2010 validation Mean squared deviation (MSD) for As, Cr and Pb for the three mapping methods based on combining the results for two 10% holdout subsets. Lowest MSD values for each element indicated in bold type. (Lne data). 2 1 n MSD = ∑ (estimated − measured ) n i =1 Element Spatial Parent Parent analyst Material Material IDW mapping mapping (GM) (IDW GM) As 0.18 0.15 0.16 Cr 0.43 0.31 0.31 Pb 0.20 0.19 0.21
  24. 24. Chromium in Talking soils – all NI With Maps 2010 New regional Parent Material mapping. Old version using IDW
  25. 25. Nickel above Soil Guideline Values (SGV) Talking Residential 130 mg/kg; Allotments 230 mg/kg With Maps 2010
  26. 26. Arsenic above Soil Guideline Values Talking Residential 32 mg/kg; Allotments 43 mg/kg With Maps 2010
  27. 27. Talking With Maps 2010 For more information Contact GSNI: gsni@detini.gov.uk GeoIndex: http://maps.bgs.ac.uk/gsni_geoindex/

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