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Overview
This datalayer was produced from 1992 U.S. Census enhanced TIGER/Line files for the fourteen counties of Massachusetts. This datalayer is known as the block group datalayer because it includes the boundaries of census block groups only. This datalayer does not contain the TIGER linework which define census blocks and is not suitable for address matching--such data is contained instead in the Census Block datalayer. This datalayer is intended for use in conjunction with Census Bureau data summarized at the census block group level, including matrices included in the 1990 STF-3a publication.
The layer is named CENSUS1990BLOCKGROUPS_POLY.
Production
The 1990 Census Block Group layer was created by the DEP GIS Group in ArcInfo Workstation using coverage data. The process involved concatenating matchids from the census county code, census tract, and block group number with water bodies coded as 'W', dissolving the original tiger/line coverages on the matchids and finally joining the dissolved coverages with the census STF-3A file at the Census Bureau-defined block group level. Block groups are areas which include a variable number of census blocks and are used as the summary level for much of the Census Bureau's demographic data. Block groups typically have a population of about 1,000 people.
A good amount of demographic data items from the Census Bureau's STF-3a matrices were appended to the polygon attribute tables of these coverages. Items MINPER and SCORE were also added to the polygon attribute table. MINPER, the percentage of minority population, was calculated by summing the following items: NONHISBLK, NONHISASN, NONHISIND, NONHISOTH, HISWHT,HISBLK,HISASN,HISIND and HISOTH, multiplying the value by 100 and then dividing the result by POP100. SCORE categories are based on the percentages of MINPER.
Attributes
he polygon attribute table contains the following data items:
| ITEM NAME | WIDTH | TYPE | DESCRIPTION |
| MATCHID-150 | 10 | C | Matchid |
| BLCKGR | 1 | C | 1990 Census Block Group |
| TRACTBNA | 6 | C | 1990 Census Tract |
| CNTY | 3 | C | 1990 Census County Code |
| HU100 | 4 | B | Number of Housing Units |
| POP100 | 4 | B | 100-percent count of Persons |
| PERSONS | 4 | B | Sample Count of Persons |
| HOUSEHOLDS | 4 | B | Households |
| WHITES | 4 | B | Caucasian |
| BLACKS | 4 | B | African American |
| AMERINDS | 4 | B | American Indian |
| ASIANS | 4 | B | Asian |
| OTHER | 4 | B | Other Race |
| HISPANICS | 4 | B | Persons of Hispanic Origin |
| NONHISWHT | 4 | B | Non-Hispanic Caucasian |
| NONHISBLK | 4 | B | Non-Hispanic African American |
| NONHISASN | 4 | B | Non-Hispanic Asian |
| NONHISIND | 4 | B | Non-Hispanic American Indian |
| NONHISOTH | 4 | B | Non-Hispanic Other Race |
| HISWHT | 4 | B | Hispanic Caucasian |
| HISBLK | 4 | B | Hispanic African American |
| HISIND | 4 | B | Hispanic American Indian |
| HISASN | 4 | B | Hispanic Asian |
| HISOTH | 4 | B | Hispanic Other Race |
| PIHH1 | 4 | B | 1 Person in Household |
| PIHH2 | 4 | B | 2 People in Household |
| PIHH3 | 4 | B | 3 People in Household |
| PIHH4 | 4 | B | 4 People in Household |
| PIHH5 | 4 | B | 5 People in Household |
| PIHH6 | 4 | B | 6 People in Household |
| PIHH7 | 4 | B | 7 People in Household |
| INC<5000 | 4 | B | Income < $5000 |
| INC<10000 | 4 | B | Income = $5000-$9999 |
| INC<12500 | 4 | B | Income = $10000-$12499 |
| INC<15000 | 4 | B | Income = $12500-$14999 |
| INC<17500 | 4 | B | Income = $15000-$17499 |
| INC<20000 | 4 | B | Income = $17500-$19999 |
| INC<22500 | 4 | B | Income = $20000-$22499 |
| INC<25000 | 4 | B | Income = $22500-$24999 |
| INC<27500 | 4 | B | Income = $25000-$27499 |
| INC<30000 | 4 | B | Income = $27500-$29999 |
| INC<32500 | 4 | B | Income = $30000-$32499 |
| INC<35000 | 4 | B | Income = $32500-$34999 |
| INC<37500 | 4 | B | Income = $35000-$37499 |
| INC<40000 | 4 | B | Income = $37500-$39999 |
| INC<42500 | 4 | B | Income = $40000-$42499 |
| INC<45000 | 4 | B | Income = $42500-$44999 |
| INC<47500 | 4 | B | Income = $45000-$47499 |
| INC<50000 | 4 | B | Income = $47500-$49999 |
| INC<55000 | 4 | B | Income = $50000-$54999 |
| INC<60000 | 4 | B | Income = $55000-$59999 |
| INC<75000 | 4 | B | Income = $60000-$74999 |
| INC<100K | 4 | B | Income = $75000-$99999 |
| INC<125K | 4 | B | Income = $100000-$124999 |
| INC<150K | 4 | B | Income = $125000-$149999 |
| INC>150K | 4 | B | Income >= $150000 |
| BLKPER | 4 | B | African American Percentage of Total Population |
| WHTPER | 4 | B | Caucasian Percentage of Total Population |
| INDPER | 4 | B | American Indian Percentage of Total Population |
| ASNPER | 4 | B | Asian Percentage of Total Population |
| OTHPER | 4 | B | Other race Percentage of Total Population |
| HISPER | 4 | B | Hispanics Percentage of Total Population |
| SUMRACE | 4 | B | Summary of Five Races |
| PUBWAT | 4 | B | Water from Public/Private Water Supply System |
| DRILLWELL | 4 | B | Water from a Drilled Well |
| DUGWELL | 4 | B | Water from a dug Well |
| OTHWAT | 4 | B | Water from Some Other Sources |
| PUBSEW | 4 | B | Public Sewer System |
| SEPTIC | 4 | B | Septic Tanks/Cesspool |
| OTHSEW | 4 | B | Other Means of Sewage Disposal |
| VAL<15K | 4 | B | House Value < $15000 |
| VAL<20K | 4 | B | House Value = $15000-$19999 |
| VAL<25K | 4 | B | House Value = $20000-$24999 |
| VAL<30K | 4 | B | House Value = $25000-$29999 |
| VAL<35K | 4 | B | House Value = $30000-$34999 |
| VAL<40K | 4 | B | House Value = $35000-$39999 |
| VAL<45K | 4 | B | House Value = $40000-$44999 |
| VAL<50K | 4 | B | House Value = $45000-$49999 |
| VAL<60K | 4 | B | House Value = $50000-$59999 |
| VAL<75K | 4 | B | House Value = $60000-$74999 |
| VAL<100K | 4 | B | House Value = $75000-$99999 |
| VAL<125K | 4 | B | House Value = $100000-$124999 |
| VAL<150K | 4 | B | House Value = $125000-$149999 |
| VAL<175K | 4 | B | House Value = $150000-$174999 |
| VAL<200K | 4 | B | House Value = $175000-$199999 |
| VAL<250K | 4 | B | House Value = $200000-$249999 |
| VAL<300K | 4 | B | House Value = $250000-$299999 |
| VAL<400K | 4 | B | House Value = $300000-$399999 |
| VAL<500K | 4 | B | House Value = $400000-$499999 |
| VAL>500K | 4 | B | House Value >= $500000 |
| MEDHHINC | 4 | B | Median Household Income |
| MEDHHVAL | 4 | B | Median Housing Value |
| MINPER | 4 | B | Percentage of Minority Population |
| SCORE | 1 | I | 0 = Percentage of Minority Pop. LE 25 2 = Percentage of Minority Pop. GT 25% and LE 50% 3 = Percentage of Minority Pop. GT 50% and LE 75% 4 = Percentage of Minority Pop. GT 75% |
| WATER | 1 | C | 'W' = Water body |