Midterm Wed minutes 2 rooms for writing, come to 200 and TAs will direct TA invigilating Includes: –Course lecture material up to this lecture –Review lab 1 and 2: process questions not specific command syntax –Use textbook to supplement lectures, no content just from textbook (UK projection info for example) Format: Short answer 1

Spatial Data Entry Textbook: Chapter 5

Learning Objectives c) Describe Spatial Data Input List and explain methods for entering spatial data (coordinates) into the GIS: –digitizing, –scanning, –Global Positioning Systems (GPS), –conversion software, –survey instruments

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

Step 1: Database Design Document Spatial Data layers

Step 2: Find Data Be careful…. Quality, screen shots vs. real data

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

GPS

Theodolite Surveying / COGO

Digitizing Points Lines polygons

Air Photo On screen digitizing

Scanning

Keyboard Entry

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

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

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

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

c) Edgematching

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

Step 5: Spatial Data Verified