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AT Unit 1 Vocab
Advanced Tools Unit 1 Vocab
Question | Answer |
---|---|
Decennial | Occurring every 10 years |
Census tracts | small, somewhat permanent subdivisions of a county. Census tracts typically contain 1,500 to 8,000 residents with the optimum population size3 being 4,000 |
census blocks | smallest geography used for the census. Blocks are define by visible features such as small city blocks. However, in rural locations, census blocks may be much larger. |
census block groups | clusters of census blocks that have the same first digit of the four-digit identification number. They usually contain 600 to 3,000 people with 1,500 residents as the optimum population size |
layer file | a file that retains all of the symbology and labels that you have set when it is saved so that they do not need to be changed when you add the data layer to another map document |
short integer | integer values that will take up to two byte of data or less; numeric values can range between -32,000 and 32,000 |
long integer | integer values that will take up to four bytes of data or less; numerical values can range between -2 billion and 2 billion |
float | a four-byte number that can store up to seven significant digits; you specify the precision (number of integers) and scale (the number of decimal points) |
double | an eight-byte number that can store up to fifteen significant digits; you specify the precision (integers) and scale (decimal places) |
text | alphanumeric characters; you specify the field length |
date | Times, dates |
blob | items such as images, multimedia or code can be stored in this type of field |
Join | when you append the fields from one table to those on another table through an attribute or field that is found in both |
relate | when the information on two separate tables are connected to one another. They are not appended and remain two separate tables, when data on one is selected the second tables data that shares the defined attribute is selected |
attribute table | table containing all attributes of a data set |
data frame | a map element that defines a geographic extent, page extent, coordinate system, and other displays properties for one or more layers of data |
FEMA | Federal Emergency Management Agency |
flood zone | an area of land where flooding is probable |
SFHA | special flood hazard area |
dissolve(within GIS) | when you aggregate(combine) features based on specific attributes |
Buffer(within GIS) | creating a polygon a specified distance around the initial feature(s) |
NLCD | National Land cover Data |
Overlay analysis | the process of taking separate data sets and finding the areas where the desired attributes from both data sets overlap |
Map template | a standardized appearance for a map which is either created by another, or is created by an individual or an organization for its own use for customization of multiple maps |
geocode | to use the address locater in ArcGIS in combination with a list of addresses to automatically place these data points based on a road database |
address locator | A system for taking a geodatabase of road reference data and formatting it to be able to geocode |
hyperlink | a typed key that connects directly to a file or website from a data point |
Raster | Data that is broken down into units-either pixels or some form of grid value |
Vector | Data that is based upon x, y points, forming points, lines, and polygons |
DEM | Digital elevation model, digital file consisting of terrain elevations for ground positions at regularly spaced horizontal intervals |
Classified | when a raster data layer's histogram is directly represented in a data layer |
Stretched | when a raster data layer's histogram is altered by applying a mathematical stretch to the values |
Effects Toolbar | A toolbar in ArcGIS which controls brightness, contrast, and transparency of a data layer |
Transparency | The level of opacity of a data layer in ArcGIS. |