Computer Applications in Engineering and Construction Programming Assignment #2 Municipal Boundaries in State Plane Coordinates

Transcription

1 CVEN 302 Computer Applications in Engineering and Construction Programming Assignment #2 Municipal Boundaries in State Plane Coordinates Date distributed : Date due : at 10:20 p.m. Return your solution either in class or in my mail box (8th Floor, CE/TTI) by the date shown above. Please show all your work and follow the rules outlined in the course syllabus. The state plane coordinate system is a convenient tool that provides direct mapping between a local Cartesian coordinate system and the global spherical coordinate system of latitude and longitude. In this assignment, we will use a provided Matlab function to convert latitude and longitude to the Texas Central Zone state plane coordinates based on the North American Datum of 1983 (NAD-83). Once points are mapped to the Texas Central Zone, simple Cartesian geometry will be used to determine whether a point is within the city limits of Wixon Valley, Texas. Section 1 introduces more engineering background and a description of Wixon Valley, Texas. The details of the programming assignment are provided in Section 2, followed by the challenge problem in Section 3. 1 Permitting and Legal Land Descriptions This assignment is analogous to a similar problem confronted by the author as he worked as an engineering intern in the early 1990 s. A large industrial company was applying for well permits for over 500 wells. Each well had to be plotted on a map and the relevant legal authority identified. Since the jurisdiction of each legal authority was easily mapped by a series of intersecting lines, he created a program to compare the coordinates of each well to each authorities boundaries and then to create a corresponding database entry that could easily be fed into the well permit application. It took almost exactly as long to create the computer program and database link as it would have taken to plot each of the 500 wells by hand and to enter the data into the well permit application. However, once the computer tool was created, it took almost no additional time to process the next 1,500 wells the company needed to permit. The State also liked the database interface, and eventually adopted it for automating their well permit application process. In Colorado, where the above program was developed, legal land descriptions are based on a nearly square system of sections, quarter-sections, and quarter-quarter-sections. In Texas, legal land descriptions are based on way points, and each land parcel is unique. Hence, it is not economical to create a general program to determine legal jurisdictions for the whole State of Texas, but in this assignment, we will test a point s coordinates against the city limits of Wixon Valley, Texas. Figure 1 shows a Google-Earth image of Wixon Valley, Texas, which is 9.5 mi north, north-east CIVIL 3136 TAMU College Station, Texas (979) FAX (979)

2 Figure 1: City Limits of Wixon Valley. Image from Google Earth, Copyright 2009 Tele Atlas. 2

3 Table 1: Latitude and Longitude of Boundary Corners for City Limits of Wixon Valley, Texas Latitude Longitude [deg] [deg] of Bryan/College Station, Texas. Table 1 provides the latitude and longitude of each corner of the Wixon Valley city limits. In this assignment, you will need to convert these coordinates to Texas state plane coordinates, find equations for the lines between points, and then build a series of IF-statements to compare a point s location to the boundaries of Wixon Valley. To convert to Cartesian coordinates, the Matlab function gcpg83.m is provided. This function is an excerpt from the FORTRAN program spcs83.exe, distributed by the National Geodetic Survey and available for download from The program provided here is only valid for the Texas Central Zone NAD-83 state plane coordinate system. 2 Assignment You will first need to use the provided function gcpg83.m, which takes latitude and longitude in decimal degrees as input, to convert the Google-Earth way points of the Wixon Valley, Texas, city limits to the state plane coordinate system. The data in Table 1 are provided for download in the file WV Boundary.dat. You will then need to use another provided Matlab function (get points.m) to generate 100 random points near Wixon Valley, Texas, for classification. Write a Matlab computer program to take the 100 random points in decimal latitude and longitude, convert them to the state plane coordinate system, compare their locations to the city limits and then classify them as within or not within the city limits. Your program should finally create a plot of the city limit boundaries together with all of the processed points, coloring the points inside the city limits as red stars and those outside the city limits as blue dots. Figure 2 shows the output from the working solution program. Organize your results using the memorandum template from the Assignments page of the course web site. In the body of the memorandum, you should briefly describe the methods used to classify each point and include a copy of the final figure produced by your working computer code. You may also discuss any problems with your code and ideas you may have to fix them. Include a listing of your Matlab program in an Appendix. Be sure to include descriptive text with the computer 3

4 x Northing (Central Texas Zone NAD 83), (m) Easting (Central Texas Zone NAD 83), (m) x 10 6 Figure 2: Classification of Points Near Wixon Valley, Texas. code or codes in the appendix. To help you get started, the following provides a skeleton for your completed program: PROGRAM Wixon_Valley.m This program reads in the locations of the boundary corners defining Wixon Valley, Texas, converts them to state plane coordinates, and then checks whether random points are inside or outside city limits. Define Variables: Fill in with appropriate text Full name UIN Date Load in the way points load WV_Boundary.dat Convert points to decimal degrees points = zeros(length(wv_boundary),2); for i = 1:size(WV_Boundary,1); 4

5 points(i,1) = WV_Boundary(i,1) + WV_Boundary(i,2)/ WV_Boundary(i,3)/3600; points(i,2) = WV_Boundary(i,4) + WV_Boundary(i,5)/ WV_Boundary(i,6)/3600; Store northing in y-component and easting in x-component [points(i,2), points(i,1)] = gcpg83(points(i,1), points(i,2)); end Load in points to classify [latp, longp] = get_points; Convert points to state plane coordinates Add commands here Classify points Add commands here Create plot figure(1) clf Add ploting commands axis equal xlabel( Easting (Central Texas Zone NAD-83), (m) ) ylabel( Northing (Central Texas Zone NAD-83), (m) ) 3 Challenge For each point, calculate the perpendicular distance in meters and bearing in degrees from North to the nearest boundary of the city limits. Output the results as a text display using the sprintf command in Matlab. 5