Intro to GIS and Remote Sensing

Introducing GIS and Remote Sensing Introduction to Mapping and GIS

Rowan University Think about all the activity occurring though out a landscape. How can we map, manage and analyze all that is going on? GIS!

US Census Data in Excel Think about keeping information about phenomenon on a landscape. How could you do it?

US Census Data in GIS GIS organizes that data with a map. But GIS is much more….

Data Types Aspatial data—data not tied to a location on the earth ’s surface Spatial data —data associated with a location on earth Much of the information we deal with daily has some spatial component.

What is GIS? Data Management Manages various kinds of GIS data including vector, raster, images, tables, other data files Data models and architectures Conversion between formats Import/export utilities Interacts with RDBMS (SQL Server, Oracle, etc…)

What is GIS? Analysis Spatially aware data Attribute and spatial query Proximity and Overlay Advanced geoprocessing techniques Decision support Flexible, customization Programming, scripting (to perform analysis)

What is GIS? Visualization Maps! Maps! Maps! If a picture is worth a 1000 words… Professional cartographic tool Charts, graphs, tables, etc… Various coordinate systems 2D and 3D Web, desktop, handheld, etc…

What is GIS? Data Management – Database View Analysis – Model View Visualization – Map View

“ G” vs. “IS” GIS uses maps to spatially analyze and search for patterns in the data that would otherwise not be found. ( Content ) GIS stores, manipulates, and displays data files and relationships in a information system using standard computing practices. ( IT ) With advances in technology, GIS users must now deal with both aspects!

The “G” “ G” = Geographic Denotes the concept of spatial location on Earth ’s surface Importance of relative location (not just where you are but where you are in relation to everything else) Theories and techniques in Geography form the basis of GIS

The “I” “ I” = Information Substance (knowledge) about location Factual and interpretative Tables + Maps + Analysis Transformation of table information into spatial context for analysis Technology and computer systems

What About the “S” in GIS? Systems Science Studies Services

Geospatial? Geographic + GIS = “Geospatial” Move in recent years to better define the industry and to focus on data and procedures (business) over geographic principles (academic) Geospatial includes all subcomponents of GIS embedded in other areas (remote sensing, GPS etc.)

Importance of Layers in GIS Geographic data = Representation of reality Reality is complex. GIS utilizes a layer approach Each layer only includes information about one type of phenomenon. Data layers must be aligned with one another

Importance of Layers Proximity Finding what is near or within a distance from a certain location or feature e.g., all houses within 100 yards of a stream Overlay Combining two layers to create new information e.g., habitat based on veg, elevation, and temp

Families of GIS Data Vector mode or coordinate based Three vector objects exist—points, lines, polygons; these are called “features.” They are represented by X,Y coordinates sometimes Z (3D), sometimes M (linear reference) Information about features is (are) called “attributes.” Two types of vector models—topological and object Topological means the data models stores relationships between vectors Vector objects exist independent of any other nearby features

Families of GIS Data Raster mode or grid cell Entire study area is covered by a grid Each cell within grid is given a value Values can be integer or decimal Data can be discrete or continuous Cell size is variable and linked to the file size of the raster data Areas outside of the grid are ignored Grid must be expanded if those areas are to be included

Modeling Geospatial Reality Real World Vector Model Raster Model

Coding Vector GIS Reality Vector Mode Model of Reality

Coding Vector GIS Reality Vector Mode Model of Reality Polygon I Polygon II Polygon III Polygon V Polygon IV node A node B node C node E node F node G node D

Coding Raster GIS Data Reality Raster Mode Model of Reality

Coding Raster GIS Data 1 1 1 1 2 3 4 4 1 1 1 2 2 3 4 4 1 2 2 2 3 3 4 4 2 2 2 3 3 4 4 4 3 3 3 3 5 5 5 5 1 1 1 1 6 5 5 5 1 1 1 1 1 5 5 5 1 1 1 1 1 1 5 5 Reality Raster Mode Model of Reality

Advantages of Vector Vector data make maps that look more like maps we are use to seeing on paper. The shapes of features are accurately represented. Vector data can have topology Vector data is good for managing attributes Vector data has smaller storage requirement Only the objects need to be represented in the database (empty space in-between is not captured)

Disadvantages of Vector Complicated data structure Software must manage many data tables Not good at representing geographic features that gradually change over location For example elevation or moisture in soil Slower processing time

Advantages of Raster Good at depicting continuously changing surfaces such as elevation or soil moisture Grid format is simple data structure Easier for computer to make analytical calculations Ideal for utilizing remote sensing images

Disadvantages of Raster Maps can be blocky looking (depending on the size of the grid cells) Cells can only be coded for one attribute when there may be more than one attribute at each location Can have very large datasets (depending on the size of the grid cell) Not topological: adjacency data structure

Remote Sensing Remotely-Sensed data is one of the most important sources of data for GIS. RS means - Acquiring data from a distance Usually uses electromagnetic energy sunlight, radar, laser Originally captured on photographic film Recent platforms utilize digital sensors

Early Remote Sensing Platforms

What kinds of devices collect the data? Aircraft High altitude Low altitude Spacecraft: Landsat SPOT Weather satellites GeoEye-1 Geosynchronous Orbit when the satellite moves at the same speed as the spinning earth – results in the camera staying over the same spot of the earth

Black and White or “ Panchromatic” Sensitive to visible light

Digital Orthographic Photos Digital photos of the earth Usually acquired by aircraft Orthographic means that the photo has all distortion removed A regular photo from an airplane will have distortion due to: Parallax – effect that distance away from the center point of a photo will always have distortion Terrain – the hills and valleys or a land area will cause distortion in the photo An orthographic photo is adjusted by computer software to make the image line up with a flat map

Digital Orthographic Photo - Infrared - 1995 You are here

Remote Sensing Mediums Black and White or “Panchromatic” Sensitive to visible light True Color Similar to color film Infrared Sensitive to infrared frequencies that can ’t be seen by humans Developed by military for identifying tanks painted with camouflage Good for evaluating conditions of vegetation Good for evaluating moisture in soil False-color adjusted When frequencies of received data are shifted to allow or enhanced human viewing Multi spectral When more than a single “band” of energy is captured Color is multi-spectral (3 bands) Some satellites can have 7 or even more “bands” of sensitivity

The Visible Spectrum The visible spectrum is only a tiny window We are blind to 99.99% of the energy in the universe We have created devices that allow us to see beyond the range of human vision

Satellite Images Weather satellite image: Winter in North America.

What are the spatial units for which data are collected? Pixel or Picture Element Smallest unit of data collection Features smaller than the pixel size can ’t be distinguished Pixel Sizes Landsat MSS = 79 meters Landsat TM = 30 meters SPOT = 10 meters IKONOS = 1 meter GeoEye-1 = 0.41 meters

Spatial resolution keeps getting better... GeoEye-1

1, 3, and 10 meters Spatial resolution keeps getting better...

Temporal Resolution Remote sensing images begin to get old as soon as they are taken. Satellites repeatedly circle the earth. Airplanes must be commissioned every time they photograph (expensive). NJ aerial photography was taken 1995, 2002, and 2007. Statewide aerials often have to be taken in multiple years. (95/97) (07/08) Turnaround is improving: NearMap’s 2cm imagery of Brisbane floods released within 1 week.

What is GIS? Now that we ’ve learned the essential elements that make up a GIS… … and have seen examples of how GIS is being used… … let ’s take a look at the big picture.

GIS Is Evolving Projects Systems Networks Integrated Coordinated Cooperative Moving to the Internet and Web Services

How is GIS used? Sometimes, the best way to learn about GIS is to see how it ’s being used….. Science Emergency management Government record-keeping Business location Environmental management Planning Crime mapping

Creating a Digital Earth . . . A Nervous System for Spaceship Earth Measuring and Integrating Spatial and Thematic Information

Violence in Darfur Image shows 2004 & 2006. Area too large and dangerous for small peacekeeping force. Violence tracked using satellite images. Article.

California Wildfires LA Times and local residents are mapping the spread of major wildfires. Using web-based GIS to present and catalog data. Article.

GeoCommons GeoCommons is a "mashup" maker Upload your data – excel or GIS and have it mapped Find data others have shared Make maps, then export to Google Earth

Response to Haitian Earthquake Users of OpenStreetMap volunteered time to update the map around Port-au-Prince . CrisisCamp volunteers are adding features such as camps, collapsed buildings & recovery efforts. How volunteers are using GIS to help in Haiti.

Intro to GIS and Remote Sensing

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