City of Birmingham
GIS data are available for approximately 140 of the 160 square miles that make up the City of Birmingham. Areas not yet developed are to the west, the Birmingport area; to the east, the area slightly beyond Huffman Road; to the southeast, the Lake Purdy area. All data are in Alabama state plane feet. Data are maintained by GIS staff, Department of Planning, Engineering, and Permits, from a variety of source documents.
Data Source Information:
Edge of pavement, building footprints, railroads, fences and hydrology were developed from existing planimetric maps photo-revised in 1984. Certain parts of the City were developed from original aerial photography flown in 1988, 1991, or 1994. As GIS is notified, updates are made to the building and pavement data layers, but the City has not flown and photo-revised the data for some time. Consequently, these data are out-of-date and should be used with caution. Official sources should be consulted. Map scale is 1:200.
Community Facilities data were developed by GIS staff based on knowledge of major landmark and public facilities. Examples include libraries, fire stations, police stations, Vulcan Park, Jazz Hall of Fame, and Civil Rights Museum, and many more.
The Roads layer is digitized as the center of the street between the edge of pavement. Attached to each street segment is an address range for the right side and left side of the street, e.g., 100-150 Main street and 101-149 Main Street. When Find Address is used, rather than Find Parcel, the address displays on the road segment that contains that address in its range. The address location is placed approximately.
Parcel graphic data are taken from the Jefferson County Tax Assessor maps and are created using a best fit to planimetric base. Twice a year, Jefferson County provides a computer file of the Tax Assessor file containing descriptive information such as tax payers' names, address, assessed value, and other valuable information. The descriptive data are related to the graphic data and do not reflect changes that occur after the data file is made by Jefferson County for Birmingham's use. The Jefferson County Tax Assessor Office is the official source for property ownership information.
Zoning was developed from the Zoning Map Books as well as changes approved by the City Council. Data are updated on a periodic basis. Due to frequent changes, official sources should be consulted.
City Limits were input based on map information supplied by the Planning Division, Planning, Engineering & Permits Department. City Limits are updated periodically. Due to frequent changes, the official source should be consulted.
Landuse is developed by the Planning Division and is the official method used to describe uses of property. These are reviewed and updated every four to six years.
Neighborhood and Community boundaries were developed from descriptions received from the Community Development Department.
City Council Districts were developed from documents obtained by the City Council Office and the City Clerk's Office.
Voting districts and voting locations are those used only for City elections. These data layers were developed under the direction of the City Clerk's Office to meet the requirement to maintain equivalent population levels in each council district after a census is completed. Once council districts are redrawn, voting precincts may need to be modified. For additional information, contact the City Clerk's Office.
Historic districts and Commercial Revitalization districts were input based on map information supplied by the Urban Planning staff.
Flood plain data were developed from Flood boundary and Floodway maps received from FEMA. FEMA maps are not drawn to scale and show floodway boundaries in relation to creeks and selected roads. These features were digitized by referencing these same features available in the GIS database.
The City Center is the official district designated as the central business district of the City of Birmingham.
Landslide susceptibility boundaries were based on an engineering study conducted in 1979 for the north face of Red Mountain. GIS staff hand digitized data displayed on 1:24000 scale USGS quadrangle maps that had been photo revised in 1978.
Sanitary sewer lines, manholes, and pump stations were input by GIS staff from existing as-builts and construction plans. No effort has been made to locate the sewers in their exact position. When possible, the lines and manholes were located on the appropriate side of the street.
Water lines, water valves, and hydrants were originally developed from maps provided by the Birmingham Water Works Board. The Birmingham Water Works Board is the official source for information about water lines and should be consulted as the final authority. In 2000 the Birmingham Fire Department was consulted to update the fire hydrants. This is now maintained based on information provided from the Fire Department.
The Official Fire District boundary was developed from boundary descriptions provided by the Birmingham Fire Department.
Cell towers were developed from coordinate and descriptive information provided by major cell tower providers.
Census data were downloaded from the U.S. Census Bureau and represent the official geography used by the Bureau when compiling each ten-year census count. Three census-related data layers are provided: blocks, block groups, and tracts. Typically the boundaries consist of roads, railroads, or other natural features. 'Blocks' are the smallest geographic unit that the Census Bureau uses to count the population. The next level of geography is the 'block group' which is a logical collection of blocks. Finally, block groups are organized to form 'tracts'. Each tract contains approximately 4,000 persons.
The census boundaries are developed from a variety of sources. The physical features for census boundaries do not meet the mapping standards used by the City. Therefore, when drawn, the census data do not visually overlay the City's GIS with much accuracy. For example, roads and census boundaries do not coincide on the screen. Care must be taken when using the census geography and GIS data together.
The above information is provided to the user about the source, accuracy level, and currency of the City of Birmingham GIS data.