Introduksjon til GIS

Transkript

1 UNIVERSITY OF BERGEN Introduksjon til GIS Gidske L. Andersen Institutt for Geografi Mål og plan for dagen Kan forklare og eksemplifisere hva GIS er Kjenner og kan anvende sentrale begreper i arbeid med GIS kan finne og lese inn data i QGIS Kan gjøre enkle GIS-analyser i QGIS Alle data finner dere på 1

2 Plan for dagen 9-10 introduksjon av dere og meg, introduksjon til GIS og grunnleggende begreper bli kjent med QGIS og innlasting av data, en projeksjonsøvelse en liten presentasjon av instituttet og hvordan dere kan bruke oss projeksjonsøvelse fortsetter, noen enkle GIS analyser What is GIS? Geographical Information Systems Geographic problems: What is the quickest route from Victoria Coach Station to Paddington Railway Station? 2

3 What is GIS? Geographical Information Systems Geographic problems: Optimum route to see all of Delhi in a day? Gill, N., And B. D. Bharath. "Identification Of Optimum Path For Tourist Places Using Gis Based Network Analysis: A Case Study Of New Delhi." International Journal Of Advancement In Remote Sensing, Gis And Geography 1.2 (2013): What is GIS? Geographical Information Systems Geographic problems: Where is most susceptible to a landslide? Distance to road Aspect Elevation Distance to stream/river Distance to faultline Slope Land use Precipitation Bedrock Feizizadeh and Blaschke,

4 GIS examples Open street map Gule sider navigation Skyss reise planning app Uber Google earth spatio-temporal 4

5 The modern beginning Canada Geographic Information System CGIS History Captioned (watch from 5:32) GIS has since developed with technology Defining GIS A Geographic Information System is a systematic integration of computer hardware, software and spatial data, for capturing, storing, displaying, updating, manipulating and analysing, in order to solve complex management problems. 5

6 Key Components of GIS GIS today Development of Open-Source GIS Software and free satellite imagery, anyone can work on GIS 6

7 GIS is everywhere Web 2.0 Spatial media! Real time integration (RTI) of GIS and GPS GIS has been «democratized» Neogeographies Variety of uses and users expert knowledge more needed than ever? 7

8 GIS integration of spatial data! GIS allows data to be integrated together Networks Topology Images 27 Main St. Vectors Surveys CAD Drawings 107 Dimensions ABC Annotation 3D Objects Addresses Terrain Attributes 8

9 Location lat, long E, N Are these positions unique? no, they lack information about datum and coordinate system! Sentrale begreper Geoiden Ellipsoiden/sfæroiden koordinatsystem Side 18 Universitetet i Bergen 9

10 Geodetisk Datum Et datum definerer posisjonen til origo, målestokk og orientering av aksene i et koordinatsystem i forhold til et objekt (fra ISO gjengitt i Iliff og Lott, 2014) Et geodetisk datum beskriver hvordan et 2- eller 3- dimensjonalt koordinatsystem er relatert til jorden (fra ISO gjengitt i Iliff og Lott, 2014) SIDE 19 Datum bestemmer hvor posisjonen (x, y) er på jordoverflaten! NB!! En posisjon er ikke unik før datum, inkludert koordinatsystem, er spesifisert! SIDE 20 10

11 Kartprojeksjoner SIDE 21 UNIVERSITETET I BERGEN Tissot s indicatrix SIDE 22 UNIVERSITETET I BERGEN 11

12 Spatial data Spatial Location/where? Temporal time/when? Thematic attribute/what? Date Location Crime type 15 Jun 5631, Rice, Houston Robbery 21 Jun 3321, Castle, Spring Assault 06 Jul 975, Fire oak, Humble Shootings Spatial entities All geographical features can be classified into 5 basic entity types Scale dependent! Figure 3.2 A simple spatial entity model for Happy Valley 12

13 Geographical data structures Two main data structures Landsat SIDE 26 13

14 Landsat 30 m Sentinel 2a 10m Side 27 RS applications Climate change research Monitoring land degradation Water management Agriculture and forest management Disaster management SIDE 28 A close-up of Virgin Gorda. Note how some of the vegetation on the south and west of the island is a bit greener, likely because it was partly shielded from winds by the hills in the center. Differences in ocean color likely stem from differences in the ocean surface; rougher surfaces scatter more light, and appear brighter and lighter. 14

15 Lidar data fra Bergen, 5 pkt/m Side 29 Universitetet i Bergen 15