The micromapST function has the ability to generate linked micromaps for any geographical area. To specify the geographical area, the bordGrp call argument is used to specify the border group dataset for the geographical area. The MarylandBG border group dataset supports creating linked micromaps for the 24 counties in the state of Maryland. When the bordGrp call argument is set to MarylandBG, the appropriate name table (county names and abbreviations) and the 24 sub-areas (countries) boundary data is loaded in micromapST. The user's data is then linked to the boundary data via the county's name, abbreviated or ID based on the table below.
data(MarylandBG)The MarylandBG border group dataset contains the following data.frames:
- contains specific parameters for the border group
- containing the names, abbreviations, and numerical identifier for the counties in the state of Maryland.
- the boundary point lists for each county area in Maryland.
- the boundaries for an intermediate level. For this border group, this boundary data is not used and set to L3VisBorders as a place holder.
- the boundaries for an intermediate level. For this border group, this boundary data is not used and set to L3VisBorders as a place holder.
- the boundary of the state of Maryland
The Maryland county border group contains 24 county sub-areas. Each county has a row in the areaNamesAbbrsIDs data.frame and a set of polygons in the areaVisBorders data.frame datasets. No regions are defined in the Utah county border group, so the L2VisBorders and RegVisBorders data.frames is not used and the dataRegionsOnly call parameter are is disabled. The L3VisBorders dataset contains the outline of the state of Maryland.
The details on each of these data.frame structures can be found in the "bordGrp" section of this document. The areaNamesAbbrsIDs data.frame provides the linkages to the boundary data for each sub-area (county) using the fullname, abbreviation, and numerical identifier for each country to the <statsDFrame> data based on the setting of the rowNames call argument.
A column or the data.frame row.names must match one of the types of names in the areaNamesAbbrsIDs data.frame name table. If the data row does not match a value in the name table, an warning is issued and the data is ignored. If no data is present for a sub-area (county) in the name table, the sub-area is mapped but not colored.
The following are a list of the names, abbreviations, and ids for each country in the MarylandBG border group.
| name | ab | id |
| Allegany | AL | 24001 |
| Anne Arundel | AA | 24003 |
| Baltimore | BL | 24005 |
| Baltimore City | BC | 24510 |
| Calvert | CV | 24009 |
| Caroline | CL | 24011 |
| Carroll | CR | 24013 |
| Cecil | CC | 24015 |
| Charles | CH | 24017 |
| Dorchester | DR | 24019 |
| Frederick | FR | 24021 |
| Garrett | GR | 24023 |
| Harford | HR | 24025 |
| Howard | HW | 24027 |
| Kent | KN | 24029 |
| Montgomery | MG | 24031 |
| Prince George's | PG | 24033 |
| Queen Anne's | QA | 24035 |
| St. Mary's | SM | 24039 |
| Somerset | SS | 24037 |
| Talbot | TB | 24041 |
| Washington | WH | 24043 |
| Wicomico | WC | 24045 |
| Worcester | WR | 24047 |
There are no alternate abbreviations or regions assocated with counties in Maryland border group.
The id field value is the U. S. state and county FIPS code.
The rowNames = "alias" or "alt_ab" and the regionB and dataRegionsOnly call parameters are not supported in the MarylandBG border group.