Creating a seamless soil data set for the Okanagan and Similkameen Valleys, British Columbia

1. Creating a seamless soil data set for the Okanagan and Similkameen Valleys, British Columbia Elizabeth Kenney1, andEryne Croquet 1kenneye@agr.gc.ca, AAFC, PO Box 1000, Agassiz, BC VOM 1A0 Background Edge Matching Before, During, and After Result • The Okanagan and Similkameen Valleys are prime agricultural areas in southern British Columbia (Figure 5). Knowledge of the soil resource information is vital for addressing competing land use, environmental, and policy issues. A number of historical soil maps and reports have been published that cover separate portions of the Okanagan and Similkameen Valley areas. • The maps (source data) for this project are: • Soils of the North Okanagan Report 101(1960) • scale 1:31,680 • Soils of the South Okanagan and Similkameen • Valleys Report 52 (1986) scale 1:20,000 • Soils of the North Okanagan Valley (1987) • Report 123 scale 1:20,000 • These three map areas needed to be amalgamated into a single spatial dataset. In order to accomplish this, borders between report areas 123 and 101 were edge-matched. The border between report areas 123 and 52 was already matched, but similar polygons were merged at the border. . Technique • Build an ArcGIS Geodatabase to contain five feature classes • Source data from Reports 52, 123 and 101 • Seamless dataset • Topology rules • Source Data • Report 101 • Four map sheets were digitized, then imported into the geodatabase • Reports 52 and 123 • Data available digitally, imported into geodatabase • Topology Rules • Polygons cannot overlap • Cannot be gaps between polygons • Reports 52 and 123 were already matched. Reports 123 and 101 were not, as shown in Figure 1. Figure 2 shows how Report 101 polygons were altered to match Report 123, which are considered better data. • Orthoimagery, available as WMS layers from the Province of BC, was used as an underlay to aid in edge-matching, as shown in Figure 2. • Verification of the accuracy of new shapes was done with Google Earth by examining soil polygons with a ‘tilted’ perspective. An example is shown in Figure 4. Figure 1: Before edge-matching Figure 2: During edge-matching: Example of reshapinga polygon using orthoimagery. Figure 4: View of Okanagan Seamless soil in Google Earth Figure 5: The Okanagan Final Seamless Soil Data Set Figure 3: After edge matching has occurred. References: GeoBC Information Services. Web Map Connection Links (http://www.ilmb.gov.bc.ca/dm/wms/data.html) Accessed June 2008 Sprout, P.N., and Kelley, C.C. 1960. Soil Survey of the North Okanagan Valley. Interim Report. British Columbia Department of Agriculture; Kelowna, B.C. U. Wittneben. 1986. Soils of the Okanagan and Similkameen Valleys. B.C. Soil Survey Report No. 52. Surveys and Resource Mapping Branch; B.C. Ministry of Environment, Victoria, B.C. Walmsley, M. and D. Maynard (Pedology Consultants Ltd.) under contract to B.C. Ministry of Environment. 1987. Soils of the North Okanagan Area. Maps with extended legends only. B.C. Ministry of Environment, Victoria, B.C.