Data acquisition and quality Flashcards
why is data so important?
Because data is the foundation of GIS, and determines
- what you can analyse
- where your analysis focuses on
- types of analysis
- quality of your analysis
What are the primary data capture methods for raster and vector data?
- Raster: digital remote sensing images; digital aerial photographs
- Vector: GPS measurements; survey measurements
What are the secondary data capture methods for raster and vector data?
Raster: scanned maps; DEMs, raster conversion
Vector: digitizing, photogrammetry, topographic surveys; toponymy data sets from atlases
what are the 5 stages in data collection projects?
planning, preparation, digitizing, editing, evaluation
How do we measure the accuracy of nominal data
With a confusion matrix.
How are accuracy and precision different?
accuracy is the distortion from the true value (the actual thing being mapped), but precision is the variation among repeated measurements/ the amount of detail in the reporting of a measurement
How to measure accuracy?
-Root mean square error is the square root of the average squared errors
What is ecological fallacy?
erroneous assumption that an overall characteristic of a zone is also the characteristic of any location or individual within the zone.
what 2 parts do Modifiable Areal Unit Problem (MAUP) consist of?
- uncertainty about what constitutes the objects of spatial study
- implications for methods of analysis commonly applied to zonal data
Distributing GIS data relies on the adoption of common standards, why?
-for various components to operate together
What is metadata?
information on the procedures used to collect and compile the data
What are 2 examples of metadata standards?
FGDC
Dublin core
a _ is a digital library containing georeferenced information
geolibrary
a _ is a digital library of geographic data and GIServices
Geoportal
What are some technology issues?
- integration of GIS into database management systems
- Competing claims from software vendors
- evaluation of technology
