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Spatial Data Entry Heywood (GIC) Chapter 5. Learning Objectives c) Describe Spatial Data Input i.List and explain methods for entering spatial data (coordinates)

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Presentation on theme: "Spatial Data Entry Heywood (GIC) Chapter 5. Learning Objectives c) Describe Spatial Data Input i.List and explain methods for entering spatial data (coordinates)"— Presentation transcript:

1 Spatial Data Entry Heywood (GIC) Chapter 5

2 Learning Objectives c) Describe Spatial Data Input i.List and explain methods for entering spatial data (coordinates) into the GIS: digitizing, scanning, Global Positioning Systems (GPS), conversion software, survey instruments ii.Data formats: shapefiles, geodatabases, grids, GeoTIFF… etc. iii.Explain methods for correcting geospatial data (topology verification, edgematching, transforming, projecting)

3 Spatial Data Entry Step 1: Database Design Document Step 2: Find Data Step 3: Input data into the computer Step 4: Spatial data editing and manipulation Step 5: Spatial data model verification

4 Step 1: Database Design Document Spatial Data layers

5 Step 2: Find Data Be careful…. Quality, screen shots vs. real data Examples –City of Vancouver Open Data site –BC government Open Data site

6

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8 Step 3: Input data Data Conversion File Transfer (Web data) –BC TRIM data (maps BC)

9 GPS

10 Theodolite Surveying

11 Digitizing Points Lines polygons

12 Air Photo On screen digitizing

13 Scanning

14 Keyboard Entry

15

16 Step 4: Spatial Data Editing and Manipulation a.topology verification b.project / transform c.edgematching d.rubber sheeting / geo-referencing

17 a) Topology verification: errors Undershoots overshoots duplicate labels No labels Pseudo nodes

18 a) Topology verification: fixed Extend Undershoot clip overshoots delete duplicate labels Add label Delete Pseudo nodes

19 b) Project Transform Project from one projection to another –Albers Equal area to Lambert Conformal Transform –digitizing coordinates to real world coordinates, –NAD27-NAD8

20 c) Edgematching

21 d) Geo-referencing (rubber sheeting) Taking historic airphoto and accurate city streets: making them fit

22 Step 5: Spatial Data Verified

23

24 Midterm: Short answer, 50 minutes Labs 1, 2 Lectures up to here Textbook chapters 1, 2, 3, 5 –Except: Chapter 2: –p 31- 34 before Topology –Box 2.6, 2.8, 2.9, 2.10 Chapter 3 –Box 3.5, –building computer worlds on p.64-p.68 Generally, terms and concepts that we did not cover in class


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