Geo-processing Techniques and Applications

1. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Fundamental of Geo-processing
techniques and its applications
Dr. Harish Karnatak
Scientist SG & HOD
Geoweb Services, IT & Distance Learning Department
Indian Institute of Remote Sensing, ISRO Dehradun
harish@iirs.gov.in
Committee on Earth Observation Satellites

2. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
GIS/Spatial
Analytics
• Desktop
• Web/Cloud
• Mobile/Tablets
GNSS &
Positioning
• Navigation
• Indoor Positioning
Earth
Observation
• Satellite Remote
Sensing
• UAV/Drone
• Aerial Survey
Scanning
• LiDAR
• TLS
• Radar
Geospatial
Technology
Geospatial
Technology
NaviC

3. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
What is GIS ?
 Geographic/Geospatial Information
 information about places on the earth’s surface
 knowledge about “what is where when”
(Don’t forget time!)
 Geographic/geospatial: synonymous
 GIS--what’s in the S?
 Systems: the technology
 Science: the concepts and theory
 Studies: the societal context
Committee on Earth Observation Satellites

4. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Questions that can answered by GIS
 LOCATION (Question: What is at ...?)
 CONDITION (Question: Where is it....?)
 TRENDS (Question: What has changed since....?)
 PATTERN(Question: What spatial pattern exist...?)
 MODELING (Question: What if....?)
Committee on Earth Observation Satellites

5. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geographic Information Technologies
 Global Navigation Satellite System (GNSS)
 a system of earth-orbiting satellites which can provide precise (100 meter to sub-cm.)
location on the earth’s surface (in lat/long coordinates or equiv.)
 Remote Sensing (RS)
 use of satellites or aircraft to capture information about the earth’s surface
 Digital ortho images a key product (map accurate digital photos)
 Geographic Navigation Satellite Systems (GIS)
 Software systems with capability for input, storage, manipulation/analysis and
output/display of geographic (spatial) information.
GNSS and RS are sources of input data for a GIS.
A GISy provides for storing and manipulating GPS and RS data.

6. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
An Inelegant Definition for GIS
 A system of integrated computer-based tools for end-to-end processing
(capture, storage, retrieval, analysis, display) of data using location on the
earth’s surface for interrelation in support of operations management,
decision making, and science.
 set of integrated tools for spatial analysis
 encompasses end-to-end processing of data
 capture, storage, retrieval, analysis/modification, display
 uses explicit location on earth’s surface to relate data
 aimed at decision support, as well as on-going operations and scientific inquiry

7. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Integrating technology consisting of:
 Remote Sensing
 Cartography and Mapping
 GNSS
 Computers
 RDBMS/ORDBMS/NoSQL
 Information Technology
 Communication technology
 Survey and field data collection
General Understanding of GIS
 Desktop GIS
 Professional GIS
 Enterprise GIS
 Mobile GIS
 Internet GIS
 Embedded GIS
 4 D GIS
 Multimedia GIS
Types of GIS
Committee on Earth Observation Satellites

8. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Types of data
 Two types of data are stored for each item in the database
 Attribute data:
 Says what a feature is
 Eg. statistics, text, images, sound, etc.
 Spatial data:
 Says where the feature is
 Co-ordinate based
 Vector data – discrete features:
 Points
 Lines
 Polygons (zones or areas)
 Raster data:
 A continuous surface
Committee on Earth Observation Satellites

9. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Layers
 Data on different themes are stored in separate “layers”.
 As each layer is geo-referenced layers from different sources can
easily be integrated using location
 This can be used to build up complex models of the real world
from widely disparate sources
Committee on Earth Observation Satellites

10. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Line and Polygon feature Buildings: polygons
Raster (image) Layer
Digital Ortho Photograph Layer:
Digital Ortho photo: combines the
visual properties of a photograph
with the positional accuracy of a
map, in computer readable form.
Vector
Layers
Layers
SRS: UTM, WGS 84
Resolution: 0.5 meters
Accuracy: 1.0 meters
Scale: 1:500 Scale
Location: Gandhinagar Slum Hyderabad, Andhra Pradesh
Committee on Earth Observation Satellites

11. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Spatial Data: examples
 Socio-economic data
 Regional health data
 Consumer / lifestyle profiles
 Geodemographics
 Environmental data
 Topographic data
 Thematic data, soils, geology
Committee on Earth Observation Satellites

12. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Spatial data storage
 Vector model
 Raster model
point
1,6
2,5
5,4
4,1
7,10
5,9
4,7
6,6
8,6
9,8
line
polygon
2,2
5 10
5
10
As geometric objects:
points, lines, polygons
As image files composed
of grid-cells (pixels)
Committee on Earth Observation Satellites

13. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Vector data model
 Advantage of the vector data format: allows precise representation of points,
boundaries, and linear features.
 useful for analysis tasks that require accurate positioning,
 for defining spatial relationship (i.e. the connectivity and adjacency) between coverage
features (topology), important for such purposes as network analysis (for example to
find an optimal path between two nodes in a complex transport network)
 Main disadvantage of vector data is that the boundaries of the resulting map
polygons are discrete (enclosed by well-defined boundary lines), whereas in
reality the map polygons may represent continuous gradation or gradual
change, as in soil maps.

14. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Raster data model
 Good for representing indistinct boundaries thematic information on soil
types, soil moisture, vegetation, ground temperatures
 As reconnaissance satellites and aerial surveys use raster-based scanners,
the information (i.e. scanned images) can be directly incorporated into GIS
 The higher the grid resolution, the larger the data file is going to be
Popular raster data formats: TIFF/GEO TIF, JPEG 2000, GML, WCS and WMS etc

15. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Raster data

16. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
source- https://www.e-education.psu.edu
1
2
3
4
5
6
1 2 3 4 5 6
Origin
(x , y)
Columns
Rows
(4,3)
Width
Hight
Popular Vector data formats:
Shape File, Geo-JSON, POSTGIS, GML, KML, WFS and WMS etc.

17. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Projection, Scale, Accuracy and Resolution
the key properties of spatial data
 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
 Scale: the ratio of distance on a map to the equivalent distance on the ground
 in theory GIS is scale independent but in practice there is an implicit range of scales for data output in any project
 Accuracy: how well does the database info match the real world
 Positional: how close are features to their real world location?
 Consistency: do feature characteristics in database match those in real world
 is a road in the database a road in the real world?
 Completeness: are all real world instances of features present in the database?
 Are all roads included.
 Resolution: the size of the smallest feature able to be recognized
 for raster data, it is the pixel size
The tighter the specification, the higher the cost.
Committee on Earth Observation Satellites

18. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
UNDERSTANDING GEO-PROCESSING
Committee on Earth Observation Satellites

19. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
What is Geoprocessing?
 Is a Computation technique used to compare,
analyze, or manipulate map layers and their
underlying geographic data to create new sets of
data or information.
 Geoprocessing techniques for Raster and vector
data analysis are used for various thematic
application including natural resource management,
disaster monitoring and management, governance
applications etc.
 Typically geo-processing is used for automation of
GIS analysis and information extraction methods. Image Source - ESRI
Committee on Earth Observation Satellites

20. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-processing with Vector Data
 Single Layer Operations- Example- Buffering or proximity analysis;
 Single Layer Geo-processing:
 dissolve operation ;
 append operation ;
 select operation ;
 merge operation;
Committee on Earth Observation Satellites

21. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-processing with Vector Data (Cont.)
 Multi Layer Operations- Typically Overlay analysis are
performed;
 Application- Site suitability analysis
 Basic GIS overlay process:
 Point-in-polygon; Polygon-on-point; Line-on-line; Line-in-
polygon; Polygon-on-line; and Polygon-on-polygon.
 Basic GIS overlay operations: Boolean operators: AND, OR,
and XOR:
 Union overlay method employs the OR operator;
 Intersection overlay method employs the AND operator;
 Symmetrical difference overlay method employs the XOR
operator;
 Identity (also referred to as “minus”) overlay method creates
an output layer with the spatial extent of the input layer.

22. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-processing with Vector Data (Cont.)
Spatial Join:
Join one dataset to another, attributes from the
first dataset (join feature) are appended to the
attributes in the second dataset (target feature)
based on the relative spatial relationship
between the two datasets i.e. geometries.
Committee on Earth Observation Satellites

23. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-processing with Raster Data
 Raster data analysis enforces its spatial relationships
solely on the location of the pixel. Raster operations
performed on multiple input raster datasets
generally output pixel values that are the result of
computations on a pixel-by-pixel basis.
 Typically arithmetic operations are performed with
raster data.
 Single Layer Analysis
 Reclassifying, or recoding;
 Raster Buffering.
Committee on Earth Observation Satellites

24. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-processing with Raster Data (cont.)
Multi-layer Layer Analysis
 Clip operation;
 Mathematical operations.
Committee on Earth Observation Satellites

25. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Raster analysis techniques
 Map Algebra;
 Zonal Statistics ;
 Contours ;
 Math Functions;
 Conditionals;
 Cost Path;
 Terrain Analysis;
 Suitability;
 Raster Processing Interpolation etc.
Committee on Earth Observation Satellites

26. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Geo-Modelling
What is Model?
“Abstract Representation of Reality.”
 A model of some process operating in space (and
time)
 there is variation across the space (and through
time)
 location is important
 the results of modeling change when locations
change
 locations must be known
Spatial Model

27. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Big Data
 Big data is the term for a collection of unstructured data sets so
large and complex that it becomes difficult to process using on-
hand database management tools or traditional data processing
applications.
 Challenges in handling Big data includes capture, curation,
storage, search, sharing, transfer, analysis, and visualization.
Committee on Earth Observation Satellites

28. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Characteristics of Big Data
Committee on Earth Observation Satellites

29. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Big Data Challenges
 Storing unprecedented volumes of data ;
 Describing what we have (Meta data);
 Finding what user need;
 Identify un-wanted data or data which can be easily
created on demand;
 Data and information quality strategies;
 Create successful tools and languages to describe and
find data, so that reuse is actively encouraged
 Enable real time analysis of data;
 Historical data for change analysis studies;
 Data and Information Security.

30. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Big Data Analytics
Big data analytics examines large and different
types of data (structured & unstructured) to
uncover hidden patterns, correlations and other
insights.
1. Descriptive analytics (What Happened and When)
2. Diagnostic analytics (Where and How it Happened)
3. Predictive analytics (What Will Happen and How)
4. Prescriptive analytics (What Should We Do)

31. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
AI, ML and DL based algorithms are Important

32. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Digital Twin (DT) technology
 The concept of Digital Twin (DT) technology provides the virtual replica of physical assets
using information collected from, IoT devices and sensors and applying advanced computation
algorithms of AI, ML and DL to understand its real time deployment and usability.
By implementing it would be
possible to understand, better the
operation and performance of each
sensor node and its utilization in
providing smart citizen services.

33. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
Applications
of Big Data
Analytics
GIS
Automative
&
Production
Media
Bank &
Insurance
Telecom
Energy
&
Utilities
Healthcare
&
Research
Cyber-
Physic
al
Models
Geo-processing of Big Geo-data have many
applications
The Big Data approach to GIS allows analysis
and decision making from huge datasets, by
using algorithms, query processing and
spatiotemporal data mining.
Committee on Earth Observation Satellites

34. I N D I A N I N S T I T U T E O F R E M O T E S E N S I N G, D E H R A D U N
harish@iirs.gov.in
Committee on Earth Observation Satellites