Data comprise the locations of springs and groundwater discharge locations from field work. Each site was visited by Dr. Tóth and marked on a 1:250000 map as well as described in detail within the INF 143 report. Vectors were georeferenced with maps and visually checked by S. Stewart.
The data represent non-topological polygonal features. Features may cross without intersecting (i.e. features may overlap). The polygons do not cross mapsheets and therefore no edgematching was performed.
Polygon features were digitized into ArcGIS by GISmo Solutions Ltd from the scanned, georeferenced versions of the 1:250000 field maps.
The following process was used:
1. The original field maps were scanned at 600 dpi into a TIF format.
2. The maps were georeferenced and because of the age of the maps, a rubber-sheeting process was required. Additional references were used in the georeferencing process. These included:
NAD27 NTS map frame neatlines (to be displayed with NTv2 transformation)
NAD83 NTS map frame neatlines
1:250000 scanned Canamatrix maps NAD83, UTM projection
1:250000 hydrography information from NTDB closely resembling features of older maps
1:20000 Provincial hydrography information
3. The hand drawn data points, lines, and polylines were then digitized into shapefiles of points, lines and polylines.
4. To reduce the file sizes, Global Mapper was used to compress the images to 8 bit color optimized palette.
5. The files were converted from GCS North American 1927 to NAD 1983 NTv2 Canada
6. The RMS error for georeferencing of each of the maps is as follows:
Brazeau 27
Calgary 5
Edmonton 29
Golden 5
Rocky Mountain House 19
Red Deer 25
Vermillion 32
Wabamun 40
Wainwright 140
7. The files were checked for accuracy by AGS staff by overlaying the points, lines, and polylines on the original scanned maps. Attributes which were documented on the field maps were checked, and additional attributes were added from the field notes for the purpose of continuity between the documents so that the attributes could be mapped for future projects. Datapoints, lines or polylines which were un-referenced or otherwise unresolved were removed.