Working With the Map and Data Table¶
The primary interface of mapdata consists of the map and data table, which are linked by geographic coordinate data and by data selections that highlight corresponding elements of both. The documentation sections linked below, and listed in the menu to the right, describe how to carry out different operations that will modify the map, the table, and data selections that are shown in both.
Marking selected map locations – Selecting and highlighting locations on the map and rows in the data table.
Un-marking selected map locations – Un-selecting locations on the map and in the data table.
Selecting data with a SQL query – Entering an expression to select and highlight data.
Panning and zooming the map – Focusing on locations of interest.
Changing location symbols and labels – Customizing the appearance of location markers.
Changing the marker symbol – Customizing the symbol used for selected locations.
Importing a new symbol – Adding a new symbol for use on the map.
Finding co-located data – Finding locations that have multiple rows in the data table.
Changing the basemap – Customizing the map background.
Using a data set with no map coordinates – Using mapdata with data sets that have no geographic coordinates.
Changing the data set – Importing a new data set to replace the current data table.
Adding or changing data – Adding columns to the data table or changing the values that are in an existing column.
Aggregating numeric data – Calculating means, medians, and other aggregates for selected numeric variables for all values of a categorical variable.
Changing the coordinate system – Applying alternate coordinate reference systems if mapped locations do not appear to be correct.
Finding unique values – Displaying all the unique values of one or more variables.
Testing cardinality – Determining whether there are one-to-one or one-to-many relationships between the values in different columns of the data table.
Finding or creating candidate keys – Identifying or creating columns that are unique for all rows in the data table or for some selected subset of rows. The Unique Values dialog can also be used to explore which columns, or combinations of column, may be candidate keys.
Creating a candidate key for geographic coordinates – Creating a unique identifier for each unique combination of latitude and longitude values.
Calculating distances between locations – Calculating distances between all pairs of selected locations, and displaying them in a table.
Saving an image of the map – Exporting the map to a graphic file.
Exporting data for selected locations – Exporting selected data rows to a CSV or spreadsheet file.