Basic GIS Concepts Basic Geographic Information System/Science (GIS) Training

Transcription

1 Basic GIS Concepts Development and Implementation of a GIS based Road Maintenance Management System for Saint Lucia Basic Geographic Information System/Science (GIS) Training Javaid Iqbal GIS Expert (PhD Scholar) March 2018

2 Contents q What is a GIS? q Components of GIS q Fundamental Types of GIS Data q Overview of GIS Architecture q GIS File Formats q Open Source GIS q GIS Applications q Who Uses GIS? q Spatial Database Infrastructure (SDI) q Global Positioning System (GPS) q Remote Sensing q Digital Elevation Model (DEM)

3 We Live in Two Worlds Natural World Constructed World Self-Regulating Managed... These Are Increasingly In Conflict

4 What is a GIS? Definition: A computer-based system to aid in the collection, maintenance, storage, analysis, output, and distribution of spatial data and information (Bolstad 2002) A GIS can: create, edit, query, analyze, and display map information on the computer

5 What is a GIS? Definition: GIS is a System of computer software, hardware and data, and personnel to help manipulate, analyze and present information that is tied to a spatial location spatial location usually a geographic location information visualization of analysis of data system linking software, hardware, data personnel a thinking explorer who is key to the power of GIS

6 Geographic Information System Geographic 80% of government data collected is associated with some location in space Information - attributes, or the characteristics (data), can be used to symbolize and provide further insight into a given location System a seamless operation linking the information to the geography which requires hardware, networks, software, data, and operational procedures not just software! not just for making maps!

7 Dr. John Snow Dr John Snow is known as the father of modern epidemiology and the father of GIS because of the famous case of the 1854 Cholera outbreak in London s Broad Street region. Source: John Snow Inc. In the 1850s, cholera was very poorly understood and massive outbreaks were a common occurrence in major industrial cities. An outbreak in London in 1854 in the Soho district was typical of the time, and the deaths it caused are shown in the map on the right.

8 Components of GIS? A Geographic Information System is not only about computers, software and electronic data. A GIS is an organised collection of : Hardware Software Network Data Procedures And people! Source: Longley et al (2005) Geographic Information Systems and Science. 2 nd Edition. John Wiley and Sons Ltd.

9 Different Kind of GIS? Desktop Application / Full Package Web Mapping / Feature Server / Server GIS Web Browser with GIS Tools / Thick Client Apps, Mashups, APIs Distributed GIS

10 Fundamental Types of GIS Data Vector A series of x,y coordinates For discrete data represented as points, lines, polygons

11 Fundamental Types of GIS Data Raster Grid and cells For continuous data such as elevation, slope, surfaces A Desktop GIS should be able to handle both types of data effectively!

12 GIS Representation Raster Vector Real World

13 Overview of GIS Architecture Spatial data are organized into layers Spatial data layers are registered States/Provinces counties roads rivers cities

14 Overview of GIS Architecture Attribute data are associated with spatial feature Attribute data are stored in tables

15 GIS File Formats Shapefile Actually a set of 3-6 files (min 3) Prob one of most widely used file type though closed, proprietary format Myfile.shp (geom), Myfile.shx, Myfile.dbf (attrs),.prj,... Move each file, or.zip all together at OS. Geodatabase Single file at OS level neatly holds all vectors & rasters PostreSQL File Geodatabase now 1Tb (and there are ways to get up to 256 Tb!) In time will likely be the only thing to use (other GIS still use shp for now) Coverage (vector); Grid (raster) Older formats you may need to know about Hybrid structure of one folder mygrid and a shared info folder shared between ALL coverages and grids in a containing folder Move ALL of these at OS or better still use ArcCatalog only!

16 Database Storage Can connect GIS to RDBMS for: Better querying Robust storage Multi-user access and sophisticated control (only one user edits electoral district at a time!) Examples: ArcSDE Create GeoDatabase in RDBMS Connects QGIS to PostgreSQL(PostGIS)

17 Open Source GIS PostGIS, MySQL Open Source DBMS implement OGC standards OGC Consortium of 482 Companies/Orgs Define Open Standards OSGeo Found n Support develop t of op n source Geospatial software GRASS Orig. US Army, now project of OS Geo GDAL (Conversion), GEOS (Geometry), rasdaman (rasters) Quantum GIS (QGIS) Another OSGeo Project MapServer export, OpenStreetMap editor, Run GRASS datasets/tools within MapTiler (uses GDAL2Tiles) Create OpenLayers/Google Maps Tilesets

18 GIS Provides Data Integration Roads Land Parcels Population Utilities Land Mines Hospitals Refugee Camps Wells Sanitation Networks Topology Images 27 Main St. 3D Objects Addresses Vectors Terrain Surveys CAD Drawings 107 Dimensions ABC Annotation Attributes

19 GIS Applications q Transportation systems Highways and interstates, subway and bus routes q Risk assessment Natural disasters, disease infection, etc. q Infrastructure Power grids, sewage, water and gas lines q Natural resource management

20 Who Uses GIS? q Public organizations Utilities (gas, cable, and water lines) Police and fire dispatch and routes Tax assessment and property records Land management q International organizations UN HABITAT, The World Bank, UNEP, FAO, WHO, etc. q Private industry Transport, Real Estate, Insurance, etc. q Government Ministries of Environment, Housing, Agriculture, etc. Local Authorities, Cities, Municipalities, etc. Provincial Agencies for Planning, Parks, Transportation, etc. q Academic and Research Institutions Globally academic and research institutions.

21 Who Uses GIS? GIS Scientist: writes algorithms GIS Specialist/ GIS Analyst: designs projects GIS Technician: works under the direction of a GIS Specialist Ancillary GIS Duties: Police and Fire Depts., NGOs, City Planning, Resource Management, Marketing/Business Increasing Skill Level From Deidre Sullivan General Public: GIS in cars, UPS, Elections in Florida

22 Spatial Data Infrastructure (SDI) Definition - the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data Part of many nation s e-governance strategy

23 GIS in Transportation Road Assets Management System Pavement quality inventory and monitoring

24 Global Positioning System (GPS)

25 What is a GPS? "GPS is a Global positioning system to determine your position on earth :eastwest north-south and vertical (longitude, latitude and altitude) GPS satellite only transmit timing data pulse, GPS units receive, only receive. GPS unit have trouble operating in rain forest, urban jungle, deep canyons, inside automobiles and roads other things. These environmental obstacles degrade positional accuracy or make it impossible to get a fix on your location.

26 Segments of GPS Space Segment Master Station Control Segment Monitor Stations User Segment Ground Antennas

27 Remote Sensing and Satellite Image Processing

28 Remote Sensing "Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information."

29 Remote Sensing Applications Area Major Applications Area of Remote Sensing q Agriculture Monitoring q Transportation Planning and Assets Management q Forest Inventory and Monitoring q Weather q Biodiversity

30 Remote Sensing Spectral Indices Few Spectral Indices of Remote Sensing q Normalized Difference Vegetation Index (NDVI) NDVI = NIR NIR q Green Normalized Difference Vegetation Index (GNDVI) GNDVI = q Soil Adjusted Vegetation Index (SAVI) Red Red q Modified Soil Adjusted Vegetation Index (MSAVI) - + NIR - Green NIR + Green é NIR - Red ù SAVI = ê + ë NIR + Red + Lú û ( 1 L)

31 Digital Elevation Model (DEM)

32 Digital Elevation Model (DEM) The representation of continuous elevation values over a topographic surface by a regular array of z-values, referenced to a common vertical datum DEMs are typically used to represent the bare-earth terrain, void of vegetation and manmade features DSM = (earth) surface including objects on it DTM = (earth) surface without any objects

33 Digital Elevation Model (DEM) Example of DSM below Example of DEM below

34 Assignments and Test Group or Individual Assignment and Presentation Test at the end of Training

35 Questions & Answers Thanks