Not all maps are appropriate as a source of information for GIS • The type of map and how it was produced, and the intended purpose must be considered when interpreting the information on maps
Data capture • Geographic data conveniently classified as Primary and secondary data • Primary Geographic data sources: • Captured specifically for use in GIS by direct measurement • Examples include: Digital Aerial photos,Digital RS images- Raster • Survey measurements,GPS measurements - Vector • Secondary Geographic data sources: • Data collected for other use and reused • Examples: Scanned maps, photographs, DEM from maps – raster data • Topo maps, Place names - Vector
Processes Outline • Project identification • Planning / consultancy and design • Data Collection • Data Capture • Image processing/ manipulation • Georeferencing • Digitizing • Map Editing • Attribute entry • Adding Labels (Text placement) • Map symbolization • Preparation of Map Layout and map output
Planning, Consultancy & Map design • - Consultative meetings/Map design • - Identification of processes/activities/tasks • - Identification of personnel • - Identification of source data • - Database design (fields and records items) • -Design Implementation (symbols, text, colour etc) • - Identification of appropriate software and hardware • - Budgeting – cost in man-hours • - Preparation of a work schedule • - Preparation of a flow diagram – work flow
Implementing the Process • Data collection • Satellite Image, Aerial Photo, Existing maps, digital data etc • Data Evaluation and Compilation • Sort the relevant data • Preparation of working environment • Create working Environment etc • Data Capture • Scanning • Digitization • Image cleaning/enhancement/processing • Use available/appropriate software • Georeferencing • Geocoding/Image registration
…… the Processes • Cropping/Clipping • Identify and delineate AOI • Digitization • Image Interpretation (use interpretation elements ) • Capture the
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- Spring '16
- prof. Maximillan tumbo