Geogc 188 M1 quizlet PDF

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GEOG C188 Midterm 1 Study online at quizlet.com/_5b3la9 1.

Working with GIS Data

*Find the data (who has what, where, in what formats?) *Obtain the data (how can you get it, is it free?) *Project the data (get it all in the same projected coordinate system) *Massage the data (Clip, intersect, merge, add attributes, etc) *Analyze the data (Buffer, calculate, measure, model) *Document your work (Create or update the metadata)

2.

Remote Sensing definition

the process of collecting data about objects or landscape features without coming into direct physical contact with them. Most remote sensing is performed from orbital or sub-orbital platforms using instruments which measure electromagnetic radiation reflected or emitted from terrain. Includes: Air Photo Interpretation and Photogrammetry, Image Processing

3.

Natural Resource and Land-use mapping

Most natural resource mapping uses remote sensing. Aerial photography has been used to produce virtually all topographic maps and most forestry, geology, land use and soils maps. Recently airborne radar and scanners as well as satellite imagery are being used for these mapping applications.

4.

History of Remote Sensing

Socrates lived from 470 to 399 BC. The teacher of Plato. Plato lived from 428 to 348 BC. He is famous for creating the notion that ideas rule the world. He was Aristotle's teacher. He lived from 384-322 BC. In 300 BCE in Greece, Aristotle philosophizing at some length about the nature of light, envisions light as a quality and not as an actual substance; as it was thought of by many at the time. He observed that some objects have the potential for transparency but this state is only rendered actual by the presence of light. Understand that some of the information we are receiving is from a different time.

Sir Isaac Newton (1666), while experimenting with a prism, found that he could disperse light into a spectrum of red, orange, yellow, green, blue, indigo, and violet. Utilizing a second prism, he found that he could re-combine the colors into white light. 1830's -Invention of the stereoscope by the Germans 1860's - American Civil War from captive balloons 1900's - Kites and pigeons used as platforms Cameras had improved and film was introduced. 1909-Wilbur Wright takes first photograph from an airplane. 5.

Aristotle Definition of Light

He then defined light as the act of, or energy of, a transparent body as such.

6.

Convergence of Information

Independent factors or multiple indicators used to deduce information. Ex: if I see signs of surrounding objects but not the object itself, i can assume that the object is there

7.

Infrared Importance

Infrared film was developed during the war to identify camouflaged military equipment. Infrared produced a useful image with non- natural or false colors (false infrared film). Most earth objects do not emit near infrared radiation but may strongly reflect it.

8.

DEMs

Digital Elevation Models =for storing terrain data. Stores regular array of points in space with spot elevation values (Z units feet, even if data UTM). Used to make terrain models: shaded relief maps, contour lines, TINS. High resolution data available in 30m and 10m resolution =can be used to create Triangulated Irregular Network (TIN)

9.

Popular Myths or Misconceptions abut Remote Sensing

1. Satellite based remote sensing does not have sufficient resolution. BUSTED! 2. Remote sensed data particularly satellite data, are not sufficiently accurate for practical applications. BUSTED! 3. Satellite data are too expensive. BUSTED! 4. Remote sensing other than aerial photography is only an experiment. BUSTED! 5. Remote sensed data are too complicated to use. BUSTED! 6. Remote sensed data are not readily available. BUSTED!

10.

Steps to Analyze RS Data

*Definition of information needs *Collection of data using RS and other techniques *Data analysis *Verification of analysis *Reporting results to those who will use information *Taking action based on the information

11.

The Art & Science of RS

*Art & science of obtaining information from a distance. *Electromagnetic energy, such as light from the Sun, illuminates objects. *Some energy is absorbed, some transmitted, and some reflected. *Objects can also emit heat as well (volcano)

12.

Basic, 1st order Elements

*Tone *Color *Resolution

13.

Tone

variation from white to black

14.

Color

multitude of combination of hue, value, and chroma

15.

Resolution

the ability of the entire photographic system, including lens, exposure, processing, and other factors, to render a sharply defined images.

16.

Second Order Elements

*Size *Shape *Texture *Pattern

17.

Size

The size of objects can be important in discrimination of objects and features (cars vs. trucks or buses; family residences, brush vs. trees, etc.)

18.

Shape

The shape of objects/features can provide diagnostic clues that aid identification.

19.

Texture

The frequency of change and arrangement of tones. The visual impression of smoothness or roughness of an area can often be a valuable clue in image interpretation.

20.

Pattern

Pattern is the spatial arrangement of objects. Pattern can be either man-made or natural. It is the regular arrangement of objects that can be diagnostic of features on the landscape.

21.

Spatial resolution

Spatial resolution is a measurement of the minimum distance. between two objects that will allow them to be differentiated from one another in an image.

22.

Components of an Electromagnetic Wave

*Wavelength *Frequency *Amplitude

23.

Electromagnetic Spectrum

24.

Federal Geospatial Data Producers

USGS US Department of the Census US Forest Service US Fish and Wildlife Service USDA NRCS Soil Survey

25.

California Geospatial Data Producers

*CA Department of Forestry and Fire Protection/Fire Resource Assessment Program *CA Department of Conservation *CA Department of Fish and Game *CA Department of Water Resources *CALTRANS

26.

How to find geospatial data?

Almost any state agency with a mission related to the natural environment will have geospatial data. Other agencies will have human environmental data that can be geo-referenced (data summarized at the census level, zip code, street address). Local agencies can also be used to find data, like local transit agencies, city and government agencies, city planning departments, etc. They often have the best data in terms of resolution but hard to figure who has the data and obtaining it.

27.

NAIP Imagery

The National Agriculture Imagery Program (NAIP) acquires aerial imagery during the agricultural growing seasons in the continental U.S. A primary goal of the NAIP program is to make digital ortho photography available to governmental agencies and the public within a year of acquisition.

28.

Earth Explorer

Created by the USGS, it is a complete search and order tool for aerial photos, elevation data, and satellite products distributed by the USGS.

29.

Cal-Atlas

The Cal-Atlas site facilitates the coordinated and sustainable development, maintenance, licensing and sharing of geospatial data and web map services by California government agencies, partners and stakeholders. California government agencies work with the California GIS Council, regional GIS collaboratives and the broader California GIS community to define the data architecture, systems, standards, agreements and processes for a fully integrated and effective California Spatial Data Infrastructure. Provides maps in RGB, Color IR, and NDVI.

30.

CNRA

California Natural Resources Agency.

31.

data.gov

The home of the U.S. Government's open data Here you will find data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations.

32.

EROS Data Center

Earth Resources Observation and Science Center, run by the USGS, studies land change and produces land change data products used by researchers, resource managers, and policy makers across the nation and around the world. Also operate the Landsat satellite program with NASA, and maintains the largest civilian collection of images of the Earth's land surface in existence, including tens of millions of satellite images.

33.

NED DEM data

The primary elevation data product of the USGS. All NED data are public domain. The NED is derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. The best available product. NED data are available nationally (except for Alaska) at resolutions of 1 arc-second (about 30 meters) and 1/3 arc-second (about 10 meters), and in limited areas at 1/9 arc-second (about 3 meters).

34.

Display X-Y data

Adds a new map layer based on XY events from a table.

35.

Geo-portal servers

36.

Tiger Data

Geoportal Server is a free, open source product that enables discovery and use of geospatial resources including datasets, rasters, and Web services. It helps organizations manage and publish metadata for their geospatial resources to let users discover and connect to those resources.

Topologically Integrated Geographic Encoding and Referencing, or TIGER, or TIGER/Line is a format used by the United States Census Bureau to describe land attributes such as roads, buildings, rivers, and lakes, as well as areas such as census tracts. 37.

What to determine from downloaded data?

* what do you have? *what's the projection? *is there meta-data? (techniques, year made, when was data collected)

38.

Federal Data Projection

often UTM, sometimes WGS (geographic coordinates)

39.

State Data Projection

often UTM or Teale Alders

40.

Local Data Projection

often in State-plane

41.

Shape file

points, lines, polygons

42.

Geodatabase

Collection of files featuring class and raster

43.

Raster

many possible extensions .sid cannot be re-projected

44.

Digitizing

the process of transforming spatial data from hard copy media (paper map) into digital form. Software often referred to as CAD (computer aid design).

45.

CAD System

Examples include AutoCAD and MicroStation used to digitize paper maps.

46.

Advantages of Computer Cartography

lower cost for simple maps faster production greater flexibility in output (scale,projection). More rapid and cost effective temporal updating

47.

Disadvantages of Computer Cartography

Computer methods do not ensure production of maps in high quality. High capital cost, though now this is much reduced.

48.

A Digital Mapping System (Microstation or AutoCAD)

Software evolved into a multipurpose CAD platform IDGS that ran exclusively on expensive mini-computers. in 1908 changed name to Intergraph. In 1986, Bentley develops a version of personal computer. Intergraph and Bentley Systems worked closely to create a program that could run on most computer platforms (PC, Mac, Windows, Unix). 49.

Digitizer

is a tool used to convert hand-drawn images into a format suitable for computer processing. Images are usually drawn onto a flat surface with a stylus and then appear on a computer monitor or screen. 50.

Manual Digitizing

51.

Digitizer setup

involves displaying a digital image on screen or placing a map on a digitizing surface, and tracing the location of feature boundaries. Coordinate data are sampled by manually positioning the puck or curser over every target point and collecting coordinate locations.

A. Digital table B. Digitizer partition C. Map D. Mouse/cursor 52.

Data Button

Mouse/cursor in Microstation Buttons.The primary button that allows you to select items, bring down pull down menus, etc.It allows you to place a POINT in your design. It allows you to select a design element.

53.

Tentative Button

Mouse/cursor in Microstation Buttons. This button allows you to place (as many times as you like) a tentative point in your design. Existing points became "highlighted" when selected with the tentative button.

54.

Reset Button

Mouse/cursor in Microstation Buttons. This button allows you to stop any on-going operation.

55.

What elements change during digitization?

Lines: Smartline Polygons : intersections Points Text: size, angle

56.

Nodes

Points that start and end a line in the digitizing process. 57.

Vertices

Points that define a line shape in the digitizing process. 58.

Undershooting

Error when nodes that do not quite reach the line or another node in digitization. Cause unconnected networks and unclosed polygons.

59.

Overshooting

Error when lines cross over existing nodes or lines. Do not cause problems when defining polygons, but may cause difficulties when defining and analyzing line networks. 60.

Snapping

Used to reduce undershoots and overshoots while digitizing. A process of automatically setting nearby points to have the same coordinates, relying on snap distance (minimum distance between features). Nodes or vertices closer than this are moved to occupy the same location. By snapping two nodes together or forcing a node to connect to a nearby line, we ensure connection between digitized lines. 61.

Splining Curves

A set of polynomial functions that join smoothly. Polynomial functions are fit to successive sets of points along the vertices in a line, with constraints that force these functions to connect smoothly (have the same slope at starting point and slope is changing at the same rate). Once functions are calculated, they may be used to add more vertices.

62.

Line-thining Algorithms

Data may be digitized with too many vertices. This can cause slower processing. Point thinking algorithms were created to reduce the number of points while maintaining line shape. The Lang algorithm, for example, vertices are removed or thinned when they are within the weed distance to a spanning line. 63.

The DouglasPeuker Algorithm

An algorithm for reducing the number of points in a curve that is approximated by a series of points. It does so by "thinking" of a line between the first and last point in a set of points that form the curve. It checks which point in between is farthest away from this line. If the point (and as follows, all other in-between points) is closer than a given distance 'epsilon', it removes all these in-between points. If on the other hand this 'outlier point' is farther away from our imaginary line than epsilon, the curve is split in two parts: From the first point up to and including the outlier and the outlier and the remaining points. 64.

Skeletonizing

Line thinning, especially if data is being converted to a vector format from raster. One of several pixels are selected to specify the position of a given portion of the line. Reduces the widths of the lines or points to a single pixel 65.

Spatially inconsistent Features

Common features may be spatially inconsistent in different spatial data layers, creating gaps and overlaps among a shared margin. May be different because features are from different source materials or differences in digitizing methods or operators. 66.

Map

"A representation, normally to scale and on a flat medium, of a selection of material or abstract features on or in relation to, the surface of the Earth"

67.

Geodesy

Geodesy is the science that deals with the measurement of the curvature, shape, and dimensions of the Earth.

68.

Paradigm shift in cartography?

69.

Evolution of a Map Projection

from communication paradigm to the analytical paradigm.

Every several years we will measure the earth. The actual shape of earth is a geoid (as close as possible). In order to model earth, we use the ellipsoid shape. There can be hundreds based on where you are, each with a different meridian. Not all ellipsoids work for different areas. When we turn it into ArcGIS we turn it into a perfect sphere and we can use only one ellipsoid thats closest to our location (like NAD 83). The problem is we have a curve, but now we want to turn it into a projected coordinate system so its flat (turning curve into flat surface). Can use many different projection coordinate systems 70.

Geoid

A surface along which the gravity potential is everywhere equal and to which the direction of gravity is always perpendicular. It is a measured surface (not mathematically defined), found via surface instruments (towed behind boats, planes, satellites, etc.), and is thought of as the approximation of mean sea level. Essentially the figure of the Earth abstracted from its topographic features. It is an idealized equilibrium surface of sea water, the mean sea level surface in the absence of currents, air pressure variations etc. and continued under the continental masses. When properly adjusted, the vertical axis of the instrument coincides with the direction of gravity and is, therefore, perpendicular to it. 71.

Ellipsoid

When we model the Earth, we model it as an ellipsoid. One axis is slightly shorter than the other (flattening due to rotational forces). The Earth has irregularities in it and deviates from a perfectly ellipsoidal shape. These deviations are due to differences in the gravitational pull of the Earth. Some fit certain regions of the globe better than others. Our ellipsoids of choice are either Clarke 1880 or the Global Reference System (GRS) 1980.

72.

Geographic Coordinate System (GCS)

It uses a three-dimensional spherical surface to define locations on the earth. Is often incorrectly called a datum, but a datum is only one part of a GCS. A GCS includes an angular unit of measure, a prime meridian, and a datum (based on a spheroid). The spheroid defines the size and shape of the earth model, while the datum connects the spheroid to the earth's surface. A point is referenced by its longitude and latitude values. Longitude and latitude are angles measured from the earth's center to a point on the earth's surface. The angles often are measured in degrees. *Spheroid with Datum, Angular Units, Prime Meridian 73.

Longitude/Latitude

Longitude measures, based on the prime meridian (running from the North Pole through Greenwich, England, to the South Pole), angles in an east-west direction...