Data Manipulation Flashcards
Georeferencing
Associating a map (such as a pdf without spatial information) or image (such as an aerial image without spatial information) with spatial locations.
Data Format Conversion
Such as converting from a vector-based dataset to a raster-based dataset
Data Transformation
Converting from the different coordinate systems; Or moving from one data structure to another data structure
Generalization can be achieved by
selection; removing details; simplification; dissolve or merge; aggregation; exaggeration
Vector (file)
A coordinate-based data model that represents features such as points, lines, and polygons.
Raster (file)
It defines space as an array of equally sized cells arranged in rows and columns, single or multiple bands. And each cell contains an attribute value.
Vector advantages
represents points, lines, and polygons accurately; more efficient that raster in storage; supports topology; interactive retrieval; enables map generalizations
Vector disadvantages
Less intuitively understood; multiple vectors overlays is computationally intensive; display and plotting vectors can be expensive
Raster advantages
easy to understand; good to represent surfaces; easy to input and output; easy to draw on a screen; analytical operations are easier
Raster disadvantages
Inefficient storage; compression techniques not efficient with variable data; large cells could potentially cause information loss; Poor at representing points, lines, and areas; Each cell can be owned by only one feature; Must include redundant or missing data;
Vector formats
Postscript, digital exchange format (CAD); Digital Line Graph (DLG); TIGER; Shapefile; Scalable Vector Graphics (SVG); ArcInfo Coverage; ArcInfo Interchange File (.eoo); Geodatabse.
Raster format
Standard; TIFF; GEO-TIFF; GIF; JPEG; DEM; BIP; BIL; RS Landsat;
3 Types of Resolution of the Raster File
Spatial resolution; spectral resolution; temporal resolution
Spatial resolution
The size of the object that can be resolved and the most usual measure is the pixel size
Spectral Resolution
Parts of the electromagnetic spectrum that are measured
Temporal Resolution
Repeat cycle. Frequency with which images are collected for the same area.
Shapefiles
.shp; .shx; .dbf;. prj; .sbn&sbx; .shp.xml;
Geodatabase
.gdb; .mdb
Coverage File
point, arc, node, route, route system, section, polygon, and region.
IMG
image
LiDAR
remote sensing technology that measures distance by illuminating a target with a laser and analyzing the reflected light
Cloud
It stores files in the cloud to be accessible anywhere. Editing data can be multi or single-user editing.
Integrated Enterprise
Data stored in big business systems to extend their analytical capabilities
Data rule and relationships
They define relationships between datasets and set rules (domains and subtypes)
Metadata
data’s origin, content, quality, and other characterisitics
Secures data
Flexibility and control over how GIS platform is deployed, maintained, secured, and used.
Versioning
allows multiple editors to edit one database by creating “duplicates” of the base data. Changes are recorded with addition and deletion tables. Versions can be created or deleted. Edits are isolated in that version until the admin merges the changes. Edits can be posted to parent version.
Data integration
Combining data from multiple sources into one unified view
