GIS Functionality
-
Upload
chandra-prakash-khatri -
Category
Documents
-
view
226 -
download
0
Transcript of GIS Functionality
-
8/9/2019 GIS Functionality
1/61
GIS FUNCTIONALITYGIS FUNCTIONALITY
Data acquisitionDigitize maps & documents
Obtain existing data set
Perform primary survey
Preliminary data processingnterpret c ass y surveye ata
Structure digital data for chosen spatial model
Data storage and retrieval
By class or attribute
Spatial search and analysis
Graphical display and interaction
-
8/9/2019 GIS Functionality
2/61
Observed
phenomena
Documents
& maps
Raw data
1.Data
acquisition
Five categories of function in GIS
Graphic
s
Structured
data
Interpretatio
n
Database 2.Preliminarydata processing
3.Storage &
retrieval
4.Search &
analysis
5.Display &
interaction
-
8/9/2019 GIS Functionality
3/61
Data AcquisitionData Acquisition
Primary data Secondary data
Three modes/ dimension : Spatial, Temporal, Thematic
-
8/9/2019 GIS Functionality
4/61
The survey techniques: (primary data acquisition)ground based studies of topography, geology and
vegetation, airborne surveys using satellites, GPS andaero-planes for natural resource management.
Much of the satellite imagery used in GIS has a groundresolution of between 4 and 80 m, useful for studies ofenvironmental ariables such as egetation andhydrology.
Photogrammetric interpretation of aerial photographs,
on the other hand, can produce highly accurate datawhich, can be used for creating and updating large-scale maps, such as at 1:500 or 1:1000 scales.
-
8/9/2019 GIS Functionality
5/61
Survey
Methods:
Remote sensing
Ground survey
InterviewsBorehole logging
Raw Data:
Scanned images
Photographs
Field documents
Geophysical logs
Census data
Primary data acquisition generates raw data from survey
-
8/9/2019 GIS Functionality
6/61
Secondary data sources
Published maps in analogue form
Socio-economic survey data
Processes:
Digitizing
Coding
Scanning
Editing
Verification
Word processing
aw a a:
Vector data
Raster data
Scanned data
Text files
Attribute data
Secondary data acquisition
-
8/9/2019 GIS Functionality
7/61
Spatial dataSpatial data
Raster
Structured array or grid of cells Pixels
Represent large range of computable
spatial objectsxamp es: a e e mages, g a eva on
Model
Vector
Basic building block is point Storage space is less
Examples :Shape files, DLG (Digital line graph)Road( line) , Well (point), Urban area (polygon)
-
8/9/2019 GIS Functionality
8/61
Raster & Vector
-
8/9/2019 GIS Functionality
9/61
Generic structure for a grid
R
ows
Resolution
Columns
-
8/9/2019 GIS Functionality
10/61
Rasters are faster...
A raster or grid maps directly onto a programming
computer memory structure called an array.
Good for representing continuous surfaces.
Rasters are a natural for scanned or remotely sensed data
Rasters are easy to understand
Spatial analytical operations are faster
Compression is easier using techniques such as Run
Length Encoding and quadtrees
-
8/9/2019 GIS Functionality
11/61
Disadvantages
Rasters are poor at representing points, lines andareas
Good only at very localized topology, and weak
otherwise
Suffer from the mixed pixel problem
Must often include redundant or missing data
Each cell can be owned by only one feature
More storage space
-
8/9/2019 GIS Functionality
12/61
The Vector ModelThe Vector Model
A vector data model uses points stored by theirreal (Earth) coordinates. Lines are built fromsequences of points in order.
Lines have a direction according to the orderingof the oints.
Polygons can be built from points or lines.
Vector data model evolved into the arc/nodevariation in the 1960s
The endpoint of a line (arc) is called a node. Arcjunctions are only at nodes
-
8/9/2019 GIS Functionality
13/61
Vector Model FeaturingVector Model Featuring
Arcs and NodesArcs and Nodes
-
8/9/2019 GIS Functionality
14/61
-
8/9/2019 GIS Functionality
15/61
Preliminary data processingPreliminary data processing
Purpose to create topologically structuredspatial data
To change data representation (Rasterization,
To modify classification schemes
To transform between cooridnate systems andmap projections
-
8/9/2019 GIS Functionality
16/61
Image classification
-
8/9/2019 GIS Functionality
17/61
A process of subdivision of given well
defined linear or areal object into cells.
Vector to raster (rasterization))
Easier and can be done with the help of
rasterization algorithms
-
8/9/2019 GIS Functionality
18/61
Reassembly of the pixels without prior
knowledge of what pixel belongs to what
object.
(d) Raster to Vector (vectorization)
-
8/9/2019 GIS Functionality
19/61
-
8/9/2019 GIS Functionality
20/61
Surface Modeling
Interpolation
-
8/9/2019 GIS Functionality
21/61
TIN: triangulated irregular network;
irregular grid.
Triangulation
-
8/9/2019 GIS Functionality
22/61
-
8/9/2019 GIS Functionality
23/61
(f) Reclassification
Use of two or more classification or coding
schemes referring to same phenomena;
Recoding; Less detailed, or generalized class:
line dropping and map dissolve.
-
8/9/2019 GIS Functionality
24/61
-
8/9/2019 GIS Functionality
25/61
Change in map projection
Coordinate transformation:
original recording the real -world units of a map
projection
map grid system
-
8/9/2019 GIS Functionality
26/61
Data storage and RetrievalData storage and Retrieval
Function to create spatial database
Spatial database contain vector, raster and attribute data
GIS requires that both data and maps be
represented as numbers.
in a physical data structure (i.e. files anddirectories).
Files can be written in binary or as ASCII text.
-
8/9/2019 GIS Functionality
27/61
Maps as Numbers:Maps as Numbers:
Raters and Vectors can be flat files if theyare simple
-
8/9/2019 GIS Functionality
28/61
Maps as Numbers: Attribute DataMaps as Numbers: Attribute Data
Attribute Data arestored logically inflat files.
i.e., matrix ofnumbers and valuesstored in rows andcolumns, like aspreadsheet.
DBMSs use manydifferent methods tostore and manageflat files.
-
8/9/2019 GIS Functionality
29/61
Geodatabase modelGeodatabase model
Stores geographic coordinates as oneattribute in a relational database table
Uses MS Access for Personal
Uses Oracle, Sybase, Ingress or othercommercial relational databases forEnterprise Geodatabases (many
simultaneous users)
-
8/9/2019 GIS Functionality
30/61
ArcGIS GeodatabaseArcGIS Geodatabase
Geodatabase
Feature Dataset
Feature Class
Workspace
eometr c
Network
Object ClassRelationship
-
8/9/2019 GIS Functionality
31/61
Feature ClassFeature Class
A feature classis a collection ofgeographic objectsin tabular format
that have thesame behaviorand the same
attributes.
-
8/9/2019 GIS Functionality
32/61
Object ClassObject Class
An object class is a collectionofobjects in tabular formatthathave the same behavior and the
same attributes.
-
8/9/2019 GIS Functionality
33/61
RelationshipRelationship
A relationship is an association or linkbetween two objects in a database.
A relationship can exist between spatial
objects (features in feature classes),non-spat a o ects o ects n o ectclasses), or between spatial and non-spatial objects.
-
8/9/2019 GIS Functionality
34/61
RelationshipRelationshipRelationship between non-spatial objects
Water
Data
Water
Quality
Parameters
-
8/9/2019 GIS Functionality
35/61
RelationshipRelationship
Relationship between spatial and non-spatial objects
Water quality data
(non-spatial)
Measurement station
(spatial)
-
8/9/2019 GIS Functionality
36/61
RelationshipRelationship
Relationship between spatial objects
Rivers that lie within
California
Two spatial objects:
rivers and California
-
8/9/2019 GIS Functionality
37/61
Vectors and TopologyVectors and Topology
-
8/9/2019 GIS Functionality
38/61
Spatial search and analysis
Spatial containment search with a rectangularwindow
-
8/9/2019 GIS Functionality
39/61
Spatial containment search
based on an existing object
-
8/9/2019 GIS Functionality
40/61
Proximal search:Buffer: spread function
connectivity
similar
-
8/9/2019 GIS Functionality
41/61
Phenomenon-based search and overlay processing
Phenomenon-based search, using a single theme or class, selects spatial
objects that (a) belong to particular categories or (b) meet specified
constraints on their spatial and non-spatial attributes.
-
8/9/2019 GIS Functionality
42/61
OR
AND
XOR
Union
Intersection
=
=
=
=
=
NOT =
Difference
Difference
=
=
Boolean and set operations can be used to combine spatial regions in overlay
analysis. The region may be regarded hare as true (shaded) and false (clear).
-
8/9/2019 GIS Functionality
43/61
Relational operators Arithmeticoperators
Greater than a + b Addition
< -
Relational and Arithmetic operatorsRelational and Arithmetic operators
a = b Equals a x b multiplication
a b Greater than or equal to a b division
a
b Less than or equal to a
b
exponential a b Not equal
-
8/9/2019 GIS Functionality
44/61
Grade 3
Agricultural land
Phenomenon-based search combining themes. Regions of alluvium
geology that coincides with agricultural land of grade 3
-
8/9/2019 GIS Functionality
45/61
Overlay analysisOverlay analysis
-
8/9/2019 GIS Functionality
46/61
ANDAND
Combinations of many themes with a proximal spatial
constraint
-
8/9/2019 GIS Functionality
47/61
Spatial analysisSpatial analysis
Interpolation and surface modeling
TIN, Grid for terrain modeling
Best path analysis and routing
Shortest route based on time and costpa a n erac on mo e ng
Optimal location of sites
Correlation, association, patterns and trends
Health management
-
8/9/2019 GIS Functionality
48/61
ArcGIS has a three part interface:ArcGIS has a three part interface:
ArcCatalog for navigating spatial data
Introduction to ArcGISIntroduction to ArcGIS
ArcMap for creating presentation graphics
ArcToolbox powerful geoprocessing tools
-
8/9/2019 GIS Functionality
49/61
Data for ArcGISData for ArcGIS
Vector Data
ArcView Shapefiles
ArcInfo Coverages
Geodatabase raw ngs
Raster Data
Most common imagery formats can beread
-
8/9/2019 GIS Functionality
50/61
Image DatasetsImage Datasets
Supported image formats: ARC Digitized Raster Graphics (ADRG)
Windows bitmap images (BMP) [.bmp]
Multiband (BSQ, BIL and BIP) and single band images[.bsq, .bil and .bip]
ERDAS [.lan and .gis]
ESRI Grid datasets
IMAGINE [.img]
IMPELL Bitmaps [.rlc]
Image catalogs
JPEG [.jpg]
MrSID [.sid]
National Image Transfer Format (NITF)
Sun rasterfiles [.rs, .ras and .sun]
Tag Image File Format (TIFF) [.tiff, .tif and .tff]
TIFF/LZW
-
8/9/2019 GIS Functionality
51/61
ArcCatalog: PreviewsArcCatalog: Previews
Using ArcCatalog you can easily preview both yourspatial datasets, and the attribute data associated withthem
-
8/9/2019 GIS Functionality
52/61
Within ArcCatalog you can easily search for databased on location and attributes stored in its metadata
ArcCatalog: Spatial SearchArcCatalog: Spatial Search
-
8/9/2019 GIS Functionality
53/61
ArcCatalog: Data ManagementArcCatalog: Data Management
ArcCatalog is provides an environment where it is safe to cutand paste spatial data into new directories, and even into the
newest ESRI spatial data structure, the geodatabase.
Additionally, several common conversion routines are
available from ArcCatalog
-
8/9/2019 GIS Functionality
54/61
ArcCatalog includes tools for viewing and editing Metadata. It even has an
option to automatically update some items in the metadata whenever a
dataset is edited
ArcCatalog: MetadataArcCatalog: Metadata
-
8/9/2019 GIS Functionality
55/61
Tools Toolbar
Menu bar
Standard Toolbar
ArcMap: Map ViewArcMap: Map View
Table of ContentsCanvas
Draw Toolbar
-
8/9/2019 GIS Functionality
56/61
Map Documents (.mxd) Saves your progress inArcMap. Does not save GIS data, just references itslocation on disk.
La er Files .l r Saves s mbolo and other dis la
Saving your work in ArcGISSaving your work in ArcGIS
properties for a data source. Again, the data source itselfis not copied, but instead referenced by the layer file
Map Templates (.mxt) If you are going to createseveral maps with a similar layout, the template can be atime-saving tool.
-
8/9/2019 GIS Functionality
57/61
ArcToolboxArcToolbox For heavy duty processing, ArcToolbox contains analysis,
conversion, and data management tools. Additionally, there is
an option to construct your own custom tools. You may set up
most tools using wizards which help take the guess work out
of some of the otherwise complicated options
-
8/9/2019 GIS Functionality
58/61
33--D AnalystD Analyst
Analysis ofland surfaceterrain astriangulated
irregularnetwork (TIN)
Visualization in3-D using Arc
Scene
Stream channel of Pecan Bayou, TX
-
8/9/2019 GIS Functionality
59/61
Spatial AnalystSpatial Analyst
Analysis of landsurface terrainas a grid
defining drainageareas andconnectivity to
stream network
Drainage network for Montgomery, AL
-
8/9/2019 GIS Functionality
60/61
Grid DatasetsGrid Datasets
Cellular-based data structure composed of square
cells of equal sizearranged in rows and columns.
and columns), as well as the value at each cell have
to be stored as part of the grid definition.Number of columns
Numberofcolumns
Cell size
-
8/9/2019 GIS Functionality
61/61
Grid DatasetsGrid Datasets
Grid datasets