Photogrammetric mapping data collection is generally a necessary but costly process. The decision regarding final formats (CADD vs GIS) of spatial data is not always clear cut. Organization, storage, manipulation, and updating of data in a CADD system are efficient and appropriate for many engineering and mapping purposes. The decision to move from CADD to GIS stems fromthe requirement or desire to spatially analyze the data. While analysis capabilities are becoming increasingly more desirable, GIS databases can be more expensive to develop than CADD data. A portion of the time and cost in photogrammetric map production is the final format of the data sets.
Factors that may affect the decision regarding CADD vs GIS include:
(1) Immediate and future uses of the spatial data sets collected.
(2) Immediate and future data analysis requirements for spatial data sets.
(3) Costs and time for each format requested.
(4) Project cost sharing and ownership.
Every attempt should be made to collect spatial data sets in the formats that will provide the most use and utility. GIS formatting costs can be minimized if the Contractor is aware of the request at the time of initial data collection. Many engineering, planning, and environmental projects can make use of and may require GIS capability in spatial data analysis. When planning a photogrammetric mapping project, both CADD and GIS formats may be required. Collection of the spatial data in both CADD and GIS will provide for the most utility of the spatial data sets and should be the first recommendation.
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