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ESPM 72 Lab 4

ESPM 72 Lab 4 - ESPM 72 Introduction to Geographical...

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ESPM 72 Introduction to Geographical Information Systems Thursday March 13th Lab 4 Due at the beginning of the next lab, April 3rd Lab Objectives 1) To examine GPS points and locate new points with satellite imagery as a reference; 2) To work with basic queries in GIS; 3) To learn georeferencing. Tool/Software Needed ArcGIS Description Start by making a folder like Z:\ESPM72\yourSID\ (Note that there should be no space in your path). Put all your spatial data into this folder. First, download data.zip from the class website. Unzip everything to your folder and check it out in ArcMap. Only display the two images now. One is DOQ and the other is QuickBird image. QuickBird is a commercial satellite owned by DigitalGlobe ( http://www.digitalglobe.com/ ). The images should look strange. Correct this by double clicking the red symbol (for the image) in the table of contents frame and setting it to band 3. Set blue to band 1. You should have this (if they look too dark, edit the Symbology, in the layer properties, such that a 2 standard deviation stretch is applied): Observe the two images carefully. Do they agree with each other? Use Google to find out the data source and provider of DOQ. Why the image taken from a sensor on the QuickBird satellite is not in alignment with DOQ? Speculate on this in your lab report. Now take a look at the GPS survey record file GPS.dbf. You can open this file with Excel and see what fields does it have but don’t make any change to it. Note that there are two attributes Longitude and Latitude , and we can create a shapefile using these two attributes as X and Y coordinates respectively, just as what we did in Lab 1. You need to define a projection to the shapefile you created. Use the projection Geographic Coordinate Systems-> North America ->
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North American Datum 1983 . Turn to Lab 2 instruction if you forget how to do that. The shapefile should be displayed in the right way at this time. The GPS data were collected by Weimin Li (our guest lecturer) for some vegetation research, so actually all the points should locate in the vegetation-covered area. Based on
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