Massachusetts Institute of Technology Department of Urban Studies and Planning 11 520 A Workshop on Geographic Information Systems 11 188 Urban Planning and Social Science Laboratory Homework 2 Extracting Census Data Simple Queries and Suitability Maps Distributed Lecture 5 Due at start of class lab Lecture 9 Question 1 Lab 8 Question 2 BEFORE STARTING ARCMAP PLEASE PAUSE AND SKIM THROUGH THE WHOLE ASSIGNMENT FIRST Getting the big picture first will help you develop a better GIS strategy and will reduce time and energy wasted A local non profit group is interested in locating a site for building a senior center in Cambridge Given your expertise in GIS you are hired as a GIS analyst by this company to help them locate the best site After a long meeting with the organization and the community you agree to run some numbers in order to get a handle on the locations and characteristics of potentially suitable Cambridge sites You settle on the following criteria to get rolling with your site selection process 1 The minimum area of land needed for the project is 1 contiguous hectares 1 hectare 10 000 square meters 2 471 acres and 1 acre 43 560 square feet 2 Ideally the site should be located near but not in a residential neighborhood The 1999 land use data is available from MassGIS or from class data folder M data camb area lu 1999 shp to classify land use Recall from Lab 2 that you can refer to MassGIS Datalayer Descriptions and Guide to User Services and specifically the documentation for the land use datalayer on the web for further discussion of land use codes The non profit organization has been promised financial assistance from a number of wealthy philanthropists and has the support of the Cambridge City Council and Mayor Thus they are capable of buying any land even if it is already developed In other words don t worry about whether or not the land is vacant or about how much it would cost to acquire the land You decide to consider any land that Was classified as open excluding urban public space and cemeteries commercial or industrial in 1999 Hint Read the land use code definitions carefully all of them Abuts but is not actually in a residential area Hint Using Select by Location with Are Within Distance Of is a way to accomplish this 3 Accessibility to the project is a major concern for the organization especially given the often limited mobility of seniors You determine that the project should be located within 200 meters of a major road MassGIS major road layer majmhda1 shp is available to assist you in determining which places meet this accessibility requirement The shapefile is located in the class data directory M data Consult the MassGIS metadata for this layer for the correct set of attribute information 4 The organization is also worried about health risks They decide that they want the site to be far more than 300 meters away from Toxic Release Inventory TRI sites as identified by the Environmental Protection Agency EPA data from their toxic release inventory databases Data from the Envirofacts database are available to identify relevant TRI site locations A shapefile of TRI facilities for Massachusetts mass tri facilities shp is stored in the M data directory Note that this constraint applies to all TRI facilities not just those located in Cambridge or the abutting towns north of the Charles River i e TRI facilities in Brookline or the Boston neighborhoods of Allston and Brighton count too We use the EPA Toxic Release Inventory database for illustrative purposes only to show how well documented external databases can be incorporated into our own local analysis In reality not all TRI sites are health risks to nearby residents and case by case analysis based on the specific nature of a site s toxic releases is warranted before rejecting locations proximate to a site The TRI facilities shapefile includes all the TRI facilities for Massachusetts in the EPA s database as of October 26 2000 and for which a latitude longitude location was provided that fell within the borders of Massachusetts Not all of the facilities in the EPA s database included latitude longitude locations and some of those with location data did not map to locations within Massachusetts as determined by intersecting the points with a theme circumscribed by the Massachusetts border 5 Accessibility by seniors with limited financial means for joining private clubs is deemed especially important Therefore you decide to narrow the criteria to census block groups where The percentage of the below poverty level senior aged 65 or over in the senior population with known poverty status is high For the purpose of this assignment a block group is considered to have a high percentage of below poverty level senior if the percentage of below poverty level seniors is at least 10 above the average for the five towns including Cambridge Arlington Belmont Somervillle and Watertown For example if you found that the overall five town percentage of impoverished seniors was 15 then you would be looking for block groups with at least 15 1 10 16 5 impoverished seniors Use the Massachusetts Block Groups 2000 layer from MIT Geodata Repository as we used in lab 5 Set the coordinate system of the coverages to Massachusetts State Plane NAD 1983 meters and set the map units to be meters Use the ma towns00 shp layer in M data directory as the town boundary As a tip you may want to select a sub set of features in both the Block groups layer and the ma towns00 shp layer that are relevant to this problem export them to your own working directory and add them to ArcMAP In this way the operation in ArcMAP is faster and at the same time you get the writing permission on these files so that you can modify them when needed More importantly you will be able notice the sliver problem The graph above shows the selected five town and the block groups that are selected using Select by Location function with intersect specified as the topological relation between two layers Many block group outside the five town boundary are also selected If you zoom into a small area across town boundary as shown below you will see why those block groups are selected The two themes have different levels of details and you would have a sliver problem if you tried to reconcile the common boundaries Find the relevant demographical data from Census 2000 Open Summary File 3 Technical Documentation pdf and search the key word POVERTY STATUS On Page 470 you will find