Maps Test 2

Differences between: GIS, GPS, and Remote Sensing (include photogrammetry)

Who was John Snow and what did he map?

In 1854, English physician, John Snow, demonstrated the problem-solving potential of maps by identifying the connection between and outbreak of cholera in London and a contaminated water supply.

Who was Henry James and what did he develop?

Photozincography (aka heliozincography) was a revolutionary way of copying photographic negatives onto zinc to be used for map making, outlines, engravings, and the reproduction of images. It was developed in the 19th century by Sir Henry James. It is, in a sense, the first copy machine produced. Vegetation, water, and developed land could all be printed as separate themes. Whilst giving the appearance of being a GIS, it does not represent a full GIS. There is no opportunity to provide an analysis of the mapped data.

Who was Roger Tomlinson and what did he do?

By the 1960s, the nuclear arms program had given rise to hardware and mapping applications and the first operational GIS had been launched in Ottawa, Canada. The early iteration of GIS was developed to store, collate, and analyse data about land usage in Canada. He was an English-Canadian geographer and has been acknowledged as the “father of GIS”. “An Introduction to Geo-Information System of the Canada Land Inventory” by R. F. Tomlinson.

five components of GIS

Software, hardware, data, people, methods

Examples of Webmapping software that was discussed in class

ArcGIS Online, Google Maps, QGIS, ENVI, Good Earth Engine

How have computers changed the mapmaking process?

Provided Significantly more accurate and reliability in the maps than anyything that could have been hand drawn. Even given the limitations, things on these maps were still very precise and exact. Made them faster, easier, and even cheaper. computer graphics for map drawing. new survey technique allowed for easier, and more reliable update to the information on tests. computer data transfer via mobile storage and networks for map sharing. computer printing technology for map production,

Advantages of computer/digital cartography compared to manual/paper-based mapmaking

More accurate and more precise. new survey technologies increase the accuracy of geographic information. computer graphics and plotting/ printing vs manual drawing. computers enable more significant digits- more precise. easy to modify existing digital base maps to create new maps. can achieve very high levels of accuracy. can store digital maps easier than paper maps. can easily adjust coordinates to their proper location (geocoding). geocoding is accomplished by first determining the actual coordinates of known points on the map. can easily overlay and visually compare geocoded maps to one another.

The design loop

Continually decreasing the amount of time and the amount of size required. refers to the process of any tool or anything that would be engineered goes through. From the creation of the idea, to the selection of the specific way it will be designed or built, to the creation of a prototype, to evaluation of the prototype, all leading into the next idea where the cycle repeats. Long and arduous process without computers. took a long time to update or to do any analysis on a map. cheaper storage and faster processing makes the design cycle shorten. Identify problem, investigation and research, brainstorm, choose solution, modeing and prototyping, testing and eval, comm the design, redesign.

The three S’s in GIS

Systems: the technology such as software and computing power used to analyze spatial info, Science: the concepts and theory we use to think about and understand the capacities along wit comprehending the underlying conceptual issues of representoing data and processes in space-time, studies: societal context that computer mapping exists in and what it can do to solve problems in those places along with social, legal, and ethical issues associated with GISy and GISc

the GI in GIS

Geographic info. info about places on the earth’s surface. knowledge about what where and when. a system for managing spatial data and associated attributes. allows for searches on geographic objects. generates views of the spatial objects (ie Maps)

The key aspects of Deuker’s definition of GIS

“A geographic information system is a special case of information systems wehre the database consists of observations on spatially distributed features, activities, or events, which are definable tin space as points, lines, or areas. A geographic information system manipulates data about these points, lines, and areas to retrivve data for ad hoc queries and analyses.” Dueker’s 1979

Raster vs. Vector

Two broad types of computer maps that we use. Every map is one of these two types. Raster map relies on square pixels of some size. Zoom in a lot to an image until it splits, those squares are pixels. Any map that can be represented by square shaped cells is a raster. each cell location has an x and y value. horizontal and vertical. each cell has easily quantifiable data value. cells have real size (biggest benefit). very manageable and accessible for data and value.Vector relies on points and the lines that are drawn directly between them. can use it to study individual singular points, we can study lines, or we can connect those lines to make polygons of any shape. can represent poiont, line, and are features accurately. lines and points created by x, y coord. much higher level of precisionl more attractive maps. measuring becomes more diffcult and complex because not consistent in size values. working with vector images more intense, more money, time.

How GIS data is structured

table of attribute information that is specifically linked to locations that are geographically identified usually with latitude and longitude. columns are individual attributes that could be spatial or non-spatial. rows are individual points, which we call features, the record or the info about each attribute column.

 Recall examples of GIS in use

Relating time, location, and type of crime. make possible the automation of acitivites involving geographic data, calculation of areas, distances, route lengths. measurement of slope, aspect, viewshed. logistics: route planning, vehicle traffic, traffic management. allow for integration of data by tying data to maps, permits the succinct communication of complex spatial patterns. provides answers to spatial queries (how many elderly live further than 10 mins at rush hour from ambulance. perform complex spatial modeling (what if scenarios for transport and disaster plannikng, resource management). 80% of local govt activity is geo based. significant portion of state level govt work, such as zoning, public works and utilities, garbage collection, land ownership. most businesses, like retail site selection vehicle tracking, natural resource exploration, civil engineering, construction. portland maps give easy access to citizens for crime data, transportation, property info, where utiities are. transport tracker. implement computers and gps on busses. can turn on aerial phtography and street view. pdx reporter anyone can install to report crimes. UPS drivers. billions of dollars a year. use analytics to torun into route that’s best for the day. handheld device has GPS chip inside. communication device. map of every driver in real time. safety perspective, how fast, how many stop signs missed. plotting new developments. all info in people’s heads onto computer system.

Remote sensing vs. Photogrammetry

photgrammetry is the art and science of making accurate measurements by means of aerial photography. analog photogrammetry uses films and hard-copy photos. digital uses digital. remote sensing is imagery of anything that we can observe and capture data about from a distance. aerial photographs were first form of remote sensing imagery.l

Who took first aerial photograph, when, and from where?

in 1858, gasper felix tournachon “nadar” takes photograph of village of Petite Biceetre in France from a hot air balloon. WWI mjor impetus for aerial phtoograpy.

Compare and contrast the three types of vantage points

vertical is captured from right above. principle point is in the middle of the photograph. view of the landscape moving outward from the principle point. camera, principle point, ground is 90 degrees. easier to analyze and work with. low oblique is taken to an angle off the side. principle point beneath the camera is not usully captured in these images; if it is, not in the center of the photo. angle between center of photo and principle point is relatively low. not able to see the horizon. high oblique photo can and do see the horizon. angle between principal point and central of photo is high.

 Additive vs. Subtractive colors, and why we would use each

additivie: blue, green, red. put together at high saturation give white. subtractive: yellow, magenta, cyan. when combined give black. red fiklter absorbs green and blue. yellow filter absorbs blue, allowing green and red to be transmitted. haze filter absorbs uv.

Types of photographs using different color filters

black and white: panchromatic- minus-blue filter used to eliminate UV and blue wavelengths (red and green observed as black and white). IR-sensitive film and IR only filter used to acquire photographs in the infrared wavelength (good to measure vegetation). UV: low contrast and poor spatial resolution due serious atmospheric scattering. color: normal color- haze filter used to abosrb UV and create true color. IR color: yellow filter used to eliminate blue and create IR color- green, red,and infrared. duis 4 bands: blue, green, red, and IR

Scale of aerial photographs

image size/real world size. focal length/ altitude above.

What is orthoimagery and why it is needed

an aerial photograph that has all the distortions due to camera tilt, scale oblicque and surface relief. photograph after correctee by ground control points or digital elevation model.

The basics of how 3D imagery works

Five key uses of GPS

location, navigation, tracking, mapping, timing

Key points in GPS history

put into place by depart of defence in 1945. sptnik 1 satellite in 1957. us navy track submarines 1960. navstar 1970s. gps became abailable to civilians 1983. standard positions service for publice and precise positioning service 1990s. 24 satellites become fully operational 1993.

How GPS combines satellites, ground stations, and receivers to function

one measurement narrows down our position to the surface of a sphere. second measurement narrows down our position to intersection of two spheres. third measurement narrows down our postion to just two points. satellites act like stars in constellation. ground station use radar to make sure satellites actually are where they say are. reciever able to calculate where u are.

NAVSTAR vs. GLONASS

gps two9nfullynoperational gloval navigations satellite systems: NAVSTAR systems and the Russian GLONASS. NAVSTAR consistsof 32 satellites owned by US and is best known satellite system. GLONASS is composed of 28 satellites.

 Where GPS works well and where it does not

does not work near sky high buildings. works good in wide open areas.

Factors that can limit/disrupt GPS accuracy and/or function

signal arrival time measurements, atmosheric effects, ephemeris, numerical calculations AI

Brief history of atomic clocks and why they are used in GPS

What is VGI and why is it popular

volunteered geographic info. spatial data. geospatial by nonprofessionals. enhance geospatial databases. eyesnon ground can be better

Where VGI data comes from

nonprofessikonals, volunteers.

What is The National Map?

What is citizen science?

What is Open Street Map project? Recall an example

USHAHIDI in Haiti open street map

GIS

Geographic information system is a computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface. GIS can show many different kinds of data on one map, such as streets, buildings, and vegetation. This enables people to more easily see, analyze, and understand patterns and relationships. It can relate seemingly unrelated data. Links locational (spatial) and database (tabular) info and enables a person to visualize patterns, relationships, and trends. provides storing and manipulating of GPS and RS data.

GPS

Satellite-based navigation system made up of a network of 24 satellites placed into orbit to collect coordinate locations. system of earth orbiting satellites which provide precise location non earth’s surface (latitude/longitudinal). only the system that gets the location itself. sources of input data.

Remote sensing (including photogrammetry)

Satellite imagery and geospatial data collected from satellite sensors or airborne cameras. Greatly enhances GIS mapping project, and serves as a source of info and data to support analysis and classification for geospatial assessment and modeling. Wide ride of applications: coastal, ocean, hazard assessment, and natural resource management. capture info about earth’s surface. sources of input data.