<p>Lab – week 10: Self-assessment by 2 Dec. 2016</p><p>Name:______</p><p>In this lab, you will create a chloropleth map of homicides in New York and then create a web map using CartoDB. </p><p>Directions: Accomplish each task and write how you did it. </p><p>Part 1: Creating the chloropleth map using QGIS Task How you did it: Open QGIS and load nyc_homicides and nyc_counties from your PostGIS database. DatabaseDB Managerright-click tablesAdd to Canvas Save each layer as a shapefile on your local machine and replace the PostGIS tables in your QGIS Project with these new shapefiles* </p><p>Create a polygon layer called ‘grid3k.shp’ containing a 3x3km grid of rectangles covering same the geographic envelope as nyc_counties </p><p>Create a new shapefile called ‘grid3k_clip.shp’ by clipping the grid3k.shp to the nyc_counties layer. </p><p>Create a new shapefile called grid3k_clip_homicides.shp having a new field called ‘homicides’ that contains the count of homicides within each polygon.</p><p>In QGIS, make a chloropleth (graduated Color Scheme: color) map showing a gradient of homicides. Experiment with color and Classification scheme: classification schemes. Which ones did you choose? # of Classes: </p><p>Take a screenshot of your map and paste it Screenshot: into the cell to the right</p><p>*we do this to speed processing time— many QGIS tools slow WAY down when PostGIS layers are included as inputs. Part 2: Recreating the analysis using CartoDB instead of QGIS Task How you did it: Import the grid3k_clip and nyc_homicides layers into CartoDB. Hint: If you’re importing shapefiles, you only need the .shp, .shx, .prj and .dbf files in your .zip folder. </p><p>In CartoDB, write an SQL statement that SQL: counts the # of homicides in each polygon of grid3k_clip. Hint: use the_geom_webmercator as your geometry field. </p><p>Part 3: Making a webmap using CartoDB Task How you did it: Now make a chloropleth map from this query showing a gradient of homicides. </p><p>Experiment with color ramps and the Color Ramp: ‘Buckets’ ‘Quantification’ drop-downs. Which ones did you choose? Quantification scheme:</p><p># of Buckets: Take a screenshot of your map and paste it Screenshot: into the cell to the right</p><p>Create a ‘visualization’ of your map Attach</p><p>Questions: 1) What are the differences between ‘Equal Interval’, ‘Natural Breaks (Jenks)’ and ‘Quantile’ classification schemes?</p><p>2) Did you prefer QGIS or CartoDB for this analysis? List some advantages and disadvantages of each. </p>