Flash Cards

Landscape Ecology Midterm notecards

Question Answer
List technologies for collecting and dealing with geographic information –Global Positioning System (GPS)
–Remote Sensing
–Geographic Information System (GIS)
Describe how remote sensing works… Satellites that orbit the Earth capture information using the electromagnetic spectrum and the signals are transmitted to the Earth and transformed to digital images
List the basic types of data that can be stored in GIS (think layer cake info) hydrology, topography, land use, utilities, soils, streets, districts, parcels
What two types of data are layers comprised of? Spatial and attribute data
What does spacial data describe? location (where)
What does attribute data describe? What, how much, when
In what two ways can layers be represented? Vector and raster format
Describe vector format points and lines
Describe raster (image) format pixels
What four properties do all geographic data have? projection, scale, accuracy, and resolution
What type of files store spatial data? shape files and geodatabases
What type of files store attribute data? stored in a data base table
What is a projection? the method by which the curved 3-D surface of the Earth is represented by X,Y coordinates on a 2-D flat map/screen (distortion is inevitable)
What is scale? The ratio of distance on a map to the equivalent distance on the ground
What is accuracy? How well the database info matches real world in terms of position, consistency and completeness
What is resolution? The size of the smallest feature able to be recognized
For raster data, what is the resolution? The pixel size
What are some "main players" for GIS software? ESRI, MapInfo, Intergraph, Bentley Systems, Autodesk
What are some "other players" for vector data? Smallworld Systems, Manifold, Maptitude
What are some "other players" for raster data? ERDAS/Imagine, ER MAPPER, Envi, PCI, CARIS, GRASS, IDRSI
What types programs are available in Arc10? ArcInfo, ArcEditor, ArcView, ArcExplorer, Browser
Describe what ArcInfo does
Describe what ArcEditor does
Describe what ArcView does
How do we incorporate into a computer application system? by using a relational Data Base Management System (DBMS)
What is a coverage? vector data format introduced with ArcInfo in 1981. Multiple physical files in a folder, composed of a data file and an info file
proprietary: no published specs and ArcInfo required for changes
Characteristics of a Shapefile comprises several physical files (with extension of .shp, .shx, .prj, .sbn, .sbx, .dbf) all of which must be present
-can only store a single feature type (point or line or polygon)
Geodatabase Multiple layers saved in a single .mdb (MS access-like) file
Which are the simplest and most commonly used format? Shapefiles
Point node.
single x, y coordinate pair
zero area
tree, oil well, city, etc
line arc
-1 dimension
-two (or more) connected x,y coordinates
-roads, streams, utilities, faults
polygon 2-dimensions
-four or more ordered and connected x,y coordinates
-first and last x,y pairs are the same
-has area and a perimeter
-census tracts, county, lake, states
what is a whole polygon (boundary structure)
polygons described by listing coordinates of a point in order as you "walk around" the outside boundary of the polygon
characteristics of a whole polygon: all data is stored into one file (could also store, inefficiently, attribute data for polygon in same file)
-coordinates/borders for adjacent polygons stored twice…may not be same, resulting in slivers(gaps) or overlap
-all lines are 'double'
What is topology? -knowledge about relative positioning
-managing data cognizant of shared geometry
what is topography? the form of the land surface, in particular, its elevation
what does topology do? it distinguishes GIS data models from non-topological data models supported by many CAD, mapping and graphics systems
what are the three C's? Connectivity, congruency(same location), and contiguity(adjacency or "next door")
what is Arc-node topology? keeps track of which arcs are connected to other arcs through shared nodes
(nodes are endpoints of arcs).
It defines length, direction, and connectivity for arcs.
what is Polygon-arc topology? expresses the relationship between the arc features and the polygon features for which the arcs create boundaries. It defines area and adjacency.
what is from-node? an arc's starting point
what is the to-node? the arc's ending point
when do arcs connect? when they share a node
Contiguity left-right topology- how polygons are associated with their neighboring polygons
how are attributes recorded? by assigning each cell a single value based on the majority feature (attribute) in the cell, such as land use type
what is raster orientation? angle between true north and direction defined by raster columns
what is a class? set of cells with the same values (e.g. type= sandy soil)
what is a zone? set of contiguous cells with the same value
what's a neighborhood? set of cells adjacent to a target cell in some systematic manner
what is GRID? is ESRI's proprietary format for storing and processing raster data
who said this: "raster is faster but vector is corrector" Joseph Berry
what is DEM? digital elevation model
a sampled array of elevations(z) that are regularly spaced intervals in the x and y directions
-disadvantage: does not conform to variability of the terrain and linear features not well represented.
what is the triangulated irregular network? a set of adjacent, non-overlapping triangles computed from irregularly spaced points, with x, y horizontal coordinates and z vertical elevations
-disadvantage: analysis involving comparison with other layers is hard
what are contour (isolines) lines? lines of constant elevation at a specified interval (example: a valley or hilltop)
graticule latitude and longitude lines that create a grid
Starting point for latitudes equator
starting point for longitudes Prime Meridian
spheroid developed to more accurately approximate the true shape of the Earth
True or false, the Earth is shaped less like a sphere and more like an ellipsoid because it bulges at the equator True
datum coordinate system which defines the position of a spheroid in relation to the center of the Earth and establishes a frame of reference for measuring locations on the surface
Different datums use a different ___________ orientation of the spheroid to geoid to determine which parts of the world keep accurate coordinates on the spheroid orientation
Name some common datums NAD27, NAD83, WGS84
What does NAD27 stand for? North American Datum of 1927
What does NAD83 stand for? North American Datum of 1983
What does WGS84 stand for? World Geodetic System of 1984
Where is the original datum from NAD27 based? When was the data collected? Meades Ranch in Kansas, land based surveys using an ellipsoid in 1866
Where is the original data from for datum NAD83 ? Where is the reference point for the datum? Satellite based system from 1980, the center of the earth is used as a reference.
True or false, NAD83 was adpoted internationally as GRS80 True
True or false, the military refined NAD83 False, the military used a refinement of WGS84
What are map projections (Projected coordinate systems)? Mathematical algorithms transform locations defined on the curved surface of the earth into locations defined on the flat surface of map aka planar representations of the Earth
In what two ways are projections grouped? Projection surface or preserved property
Describe the three main types of projection surfaces Azimuthal (planar)
Cylindrical (projection onto cylinder then unrolled)
Conic (projection onto a cone and unrolled)
Describe the four main types of preserved property Conformal (preserves local angles and shapes)
Equivalent (represents areas in correct relative size but not absolute size)
Equidistant (distance from a single location to all other locations are preserved)
Azimuthal (retains certain accurate directions
True or false, GCS (geographic coordinate system) has been projected to a flat surface False, GCS consists of latitude and longitude lands that have NOT been projected on a flat surface
Name the units for GCS DMS: degrees, minutes, seconds
DD: decimal degrees
What is most ESRI data's in? GCS_North_American1983 (Geographic Coordinate system, NAD83)
True or false, GCS can locate exact positions on the surface of the Earth? true
True or false, GCS is good for measuring distances between areas False, distances between parallels and meridians are not uniform
Which projections should be chosen for low-latitude areas near the equator? Cylindrical
Which projections should be chosen for mid-latitude areas? Conical
Which projections are best for polar regions? Azimuthal
What are the commonly used projections for worldwide data? Plate Carree, Robinson, Sinusoidal
Describe the Plate Carree projection Cylindrical, polar regions distorted, preserves eastings and northings
Describe the Robinson projection Pseudo-cylidrical, preserves neither area nor distance
Describe the Sinusoidal projection Meridians based on sine function, preserves area (equivalent)
What are common projections used in the US? UTM, State Plane, Albers Equal-Area Conic
Describe the UTM (Universe Transverse Mercator) projection Pseudo-cylindrical projection, units are meters, used by state governments, splits into 60 longitudinal zones, bad for polar regions
True or false, Georgia is in UTM zone 17? False, Georgia lies in UTM zones 16 and 17
Describe SPC (State Plane Coordinates) projection Specific system for each state, some states divided by states, each system has a specific projection, high accuracy, most county and city governments use this
True or false, Baldwin County is in system GA-E True
Describe Albers Equal-Area Conic Used in most US national maps and sometimes for World Atlases
What makes up a coordinate system? The entire projection with datum which equate a spatial reference
True or false, ArcMap projects multiple data sets that don't have to be in the same projection True, this is called projecting,"On the Fly"
True or false, ArcMap sets the projection of your Data Frame to be the last data set added? False, the projection is set to be the FIRST data set
geographic transformation converts geographic coordinates in one datum to corresponding coordinates in the other
what are the 2 main types of geodatabases? personal and file geodatabase
personal geodatabases store raster data. true or false? false. they do not store raster data.
file geodatabases have what extension? .gdb
personal geodatabases have what extension? .mdb
which geodatabase is easier to create and manage and have virtually no size limit and are not tied to windows? file geodatabases
___________ allow us to group data for a particular area or types of data into one centrally managed package. geodatabases
this allows for interactive relationships between datasets (feature classes) within feature datasets (aka, topology) geodatabases
this helps store data in such a way that file sizes are much smaller and hard-drive space is conserved geodatabases
what is a feature class? a collection of features with the same geometry type (point, line, polygon) and same attributes
define a feature dataset collection of feature classes that share the same spatial reference (same location)
topology rules are used to establish relationships among feature classes
what are tables used for to store non-spatial data
feature classes, feature datasets, tables, and raster datasets are all created in which program? ArcCatalog
all feature classes have a field named what? "shape"
feature classes can stand alone within _______ or be contained within _______, _________, or __________ geodatabases, shapefiles, coverages, or feature datasets
what is the x,y tolerance for? it is used to set the minimum distance between coordinates
what is the x,y resolution? it defines the number of decimal places (sig digits) used to store the coordinates. the numeric precision used to store the x,y coordinate values
2 primary reasons feature datasets are used: 1. organize thematically related data into a single database
2. organize related feature classes for building spatial relationships between these feature classes (topology)
when creating a new feature dataset, you must define its _______ _________ spatial reference
spatial reference projection
x,y,z and M (linear measurements) value tolerances
3 primary field data types in ArcGIS…what are they? Numeric, Text, and Date
what is short integer? can store 5 significant digits (no decimals)
long integer can store 10 significant digits (no decimals)
floating point stores decimal points up to 7 significant digits
double-precision stores decimal points up to 15 significant digits
what's a geodatabase schema? a fancy name for the properties you set up for your geodatabase. (tables, feature classes, datasets, topology and their properties)
where do you create a geodatabase? in ArcCatalog
what do domains do? they allow you to set a predefined list of options for how a field can be populated- this reduces typos and data input effort
you complete the ______ _____by adding the following fields: construct date, location, description, activity type feature class
feature classes are created in what program arcCatalog
you go into _________ to put in line data into this feature class ArcMap
if a dataset has no Z coordinates what does that mean it is not a 3D dataset
when you can drag data into a feature dataset this is only possible when? they share the same spatial reference
2 types of data collection…what are they? primary and secondary
primary data collection data that is created in house.
the most expensive part of GIS
secondary data collection data that already exist
what does a digitizing tablet do? it sends an electrical impulse from the edges read by the puck to determine location.
what is on screen digitizing? when the original map is scanned and georeferenced.
features are captured using the mouse
text files if you have a text file or a table with x,y values you can directly import them into arcGIS
excell or access (or other DB)
GPS data
DEM digital elevation model
NED national elevation dataset
NHD national hydrography dataset
DRG digital raster graphic
DLG digital line graph
DOQQ digital ortho quarter quad
GNIS Geographic names information system
LULC land use land cover
NLCD national land cover data
hypsography contours and supplementary spot elevations
TIGER topologically integrated geographic encoding and referencing
NCDC national climate data center.
the world's largest active archive of weather data
image server a server generates an image of a map and sends it to a browser or plugin
feature servers a server selects the features you need and sends them to your client.
the client can be ArcMap, arcReader, or a custom viewer
2 internet map servers image and feature servers
commercial data many data products are repackaged free data.
street map and address data
remote sensing data sets
standards agreed-upon ways of doing, describing, or delivering something
_____ _________ are very important with the number of organizations using and producing data and because of spatial data can now be manipulated so easily with GIS software data standards
4 areas of spatial data standards media standards.
data format standards.
accuracy standards.
documentation standards-metadata.
media standards-examples physical form of transfer.
cd's, DVDs, tapes
format standards aid in the ______ of data between companies, agencies, and individuals transfer
accuracy standards help to: document the quality of positional and attribute values.
it's very expensive. often one of the last things done. can have dramatic impacts on spatial analyses
documentation standards: define how data is described, tell us how data was manipulated/created, tell how data is stored and in what format, allows for users to quickly access usefulness
5 different aspects of data: 1. identification.
2. data quality
3.spatial reference and organization information
4. entity and attribute information.
5. distribution
CSDGM sat_flash_1 standard for digital geospatial metadata
all us government units are required to adhere to the _____ when documenting and distributing spatial data CSDGM
What is a map? Generalized view of an area, usually same portion of Earth's surface as seen from above at a greatly reduced size, any geographical image of the environment, two dimensional representation of the spatial distribution of selected phenomena
Cartography the science, art and technology of making using and studying maps
Important elements of a map Title, legend, scale, orientation, metadata (data source, projection, datum, map creator and date)
optional elements-locator map, inset map, neatline
Describe map scale a ratio of distance on the map to distance on the ground
True or false, a large scale map covers a small area True
Describe a qualitative point symbol It indicates a location and can describe a location
Describe a quantitative point symbol it shows a distribution and can indicate a value via graduated symbols
Describe a line symbol One dimensional, commonly describe borders and roads, can also be used for isolines and flow lines
Isoline connect same values
Describe area symbols can be divided in to kind (qualitative) area symbols and value(quantitative) area symbols
Cartograms distort area to show value
Primary vector analysis tools selection tools, map overlay tools, single input analyses, spatial join
Describe selection tools Select by attribute: query the attribute table or data
Select by location: select features from one layer that are within a certain area with another data layer
What are the map overlay tools available? Clip, erase, intersect, union, identity, merge, append
Describe the 2 types of single input vector analyses Dissolve: creates new shape-file that merges adjacent polygons
Buffer: creates buffer polygons to set distance around input features
Describe spatial join allows you to summarize one layer by the attributes of another based upon the spatial location of each dataset
spatial data describes location, where
attribute data specifies characteristics at a location (what, how much, and when)
How are geographic features represented in GIS features are grouped into layers based on similar characteristics using vector and raster data
Vector data model coverage or shapefile
Raster data model GRID or IMG- img jpg tif ect
Coverage file format stores vector data, multiple physical files in a folder, introduced in 1981 with ArcInfo
Shapefile vector data format with physical files like: shp, shx, prj, sbn, sbx, dbf that all must be present
True or false, shapefiles can store multiple feature types False, shapefiles can only store a single feature type like point, line or polygon, introduced in 1993
Geodatabase multiple layers saved in a single .mbd or .gdb, introduced in 2000
True or false, shapefiles are the simplest and most commonly used format for vector spatial data True
Describe the files that must be present for a shapefile to function dbf: database file stores feature attributes
prj: projection file stores coordinates
shp: contains feature geometry
shp.xml: metadata
shx: spatial index file
True or false, in a geodatabase, all data doesn't have to be in the same spatial extent false, all data must be in the same spatial extent
True or false, in relational geodatabases, both spatial and tabular data are stored True
Types of vector data point, line, polygon
topology knowledge of relative spatial positioning of features and how features are connected and which features are adjacent to each other
topography the form of the land surface and particularly elevation
True or false, whole polygons from vector data can store topological information False
Name the three Cs from the concept of topology Connectivity, congruency, contiguity
Topology rules for coverages Each arc has beginning node and ending node which determines direction, arcs connect to other arcs at nodes, connected arcs form polygon boundries (arc coordinates are only stored once if they are common bw 2 polygons) Arcs have polygons to left and right
Arc node topology keeps track of which arcs are connected to other arcs through shared nodes, defines length, direction and connectivity for arcs
from-node starting point of an arc
to-node ending node of an arc
polygon arc topology expresses the relationship between arc features and the polygon features for which the arcs create boundaries, defines area adjacency,
True or false, two arcs are adjacent if they share an arc true
left-right topology refers to contiguity-how polygons are associated with their neighboring polygons, each arc has a list of which polygons are on the right side and which are on the left
raster data area covered by grid with equal sized cells, describes location and connects attributes
Describe location of raster data this is calculated from each cell from origin of the grid
Describe attributes of raster data recorded by assigning each cell a single value based on the majority feature in the cell (think like land use)
True or false, raster data has a complex data structure false, it has simple data structure, directly stores each layer as a single table and computer database management system is not required
True or false, single values are associated with each cell in raster data true
List file formats for raster spatial data GRID, JPEG, TIFF, MrSid
True or false, to use raster data for analysis, it must be converted to a grid True, the data can only be displayed in JPEG TIFF and MrSid
What are DRGS digital raster graphics, digital versions of topographic maps
DOQQs Digital orthophoto quarter quads
Describe what features that vector data models are best for features with discrete boundaries like property lines, political boundaries, and transportation
Describe what features that raster data models are best used for elevation, temperature, soil type, land use, ground cover
True or false, ArcMap cannot read and overlay all three types of data False, ArcMap can read and overlay all three data types
There are three ways to represent digital terrain models Raster based DEMs, Vector based TINs, Vector based contour lines
Describe DEMS digital elevation model, regular spaced set of elevation points including x values
Describe TINs triagulated irregular networks, irregular triangles with elevations at the three corners
Described vector based contour lines must be converted to raster or TIN for analysis, lines joining points of equal elevation at specified intervals
True or false, geodatabases are native to and only work with ArcGIS true
Personal databases extension: mdb, can only be edited by one user per time, 2 gig max size, doesn't store raster data
File geodatabase extension: gdb, virtually no size limit
Describe feature classes collection of features with same geometry type and same attributes
describe feature datasets collection of feature classes that share the same spatial reference, topology rules are used to establish relationships among feature classes
describe tables (geodatabases) used to store non-spatial data
describe raster datasets (geodatabases) store any supported raster file type: GRID, TIFF, MRSID, JPEG, ERDAS, IMG
True or false, all geodatabases are created and managed in ArcMap False, all geodatabases are created in ArcCatalog
True or false, feature classes can stand alone within geodatabases or be contained within shapefiles, coverages, or feature datasets True
Feature classes are used for two primary reasons, what are they? Organize thematically related data into one database, organize related feature classes for building spatial relationships *like topology)
DRG Digital raster graphic, scans of USGS topo maps
GNIS Geographic names information system contains info about physical and cultural geographic features of US and its territory
NHD National hydrography data set, contains info about naturally occurring and constructed bodies of water
LULC Land use and land cover data, consists of historical land use and land cover classification data
NLCD National land cover data using 21 classes over United States and derived from 1990s landsat data
TIGER Topologically integrated geographic encoding and referencing,
NOAA Oceans
NCDC National Climatic data center
What is metadata made of? Identification, data quality, spatial reference and organization information, entity and attribute information, distrobution,
US Metadata standards, list the 10 types of info identification, data quality, spatial data organization, spatial reference coordinate system, entity and attribute, distribution and options for obtaining the data set, currency of the metadata and responsible party, citation, time period, contact

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