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Each TIFF file ranges between 35-40MB in size.Unlike DVRPC\u2019s more recent aerial imagery (2000 and later), the historical aerials are not \u201corthorectified\u201d or \u201corthocorrected\u201d. In other words, they are simply aerial images with no spatial reference or uniform scale. Through the process of georeferencing, the scanned images can be assigned a spatial reference which will enable them to be used more readily in a GIS environment. That said, georeferencing is not orthorectifying or orthocorrecting. What it does allow is for the scan to be displayed relative to other spatially referenced GIS layers. A georeferenced scan does not have the properties of an actual orthoimage. 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