Grand River Watershed Orthomosaic 2000

Description:

This digital orthomosaic covers the entire Grand River Watershed. The watershed extends from the headwaters of the Grand River near Luther Marsh Reservoir to the mouth of the Grand River at Port Maitland on Lake Erie. Aerial photography was flown between April 4th-30th, 2000, and was provided to the Library by the Grand River Conservation Authority in September 2004. The pixel resolution of the orthomosaic is 30cm.

Spatial Reference and Data Type:

This orthomosaic, because of its large file size is divided into two halves, a north and a south half, with the line of division passing through the City of Waterloo, and more specifically, through the UW south campus. These georeferenced mosaics are available in UTM coordinates; horizontal datum is NAD83. They are stored as compressed MrSID data files, with accompanying SDW world files. The mosaics are approximately 2GB each.

Data Access:

In order to access this electronic resource, please visit the Gospatial Centre Reference Desk during reference hours. Library reference staff are available to provide further information about this data set and to deliver data upon request.

Data Manipulation:

There are public workstations in the Geospatial Centre that provide access to both ArcGIS and ArcView software programs, program extensions and data manipulation utilities. Patrons may use the GIS and image processing software in the library to view and manipulate the data. UW faculty, students and staff may copy these data to other media (for example: CD, DVD or Zip disc) for use elsewhere.

Data Output:

Given the large size of each of these mosaics, it is not practical nor is it useful to export the entire image unless at very low resolution. ArcGIS may be used to export small sections of the mosaic in a choice of bitmapped formats (also known as raster graphics) including JPG, TIFF, GIF, and BMP or in a choice of vector graphics formats including AI, EPS, and SVG. Yet another option is PDF. The MrSID Geoviewer may also be used to export a small selection of the mosaic as either a TIFF or GeoTIFF image. The user defines the output resolution.

Citation:

Grand River Watershed Orthomosaic 2000 [computer file]. Cambridge, Ontario: Grand River Conservation Authority, [2000].

Sample View of the Data:

Click Image to zoom in.

, Library Assistant

May 25, 2012

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Maps • Geospatial Centre