Wednesday, March 22, 2017

Lab 7

NAD 1983 contiguous USA Albers XLS FILE- An XSL style sheet is, like with CSS, a file that describes how to display an XML document of a given type. XSL shares the functionality and is compatible with CSS2 Select by Attributes-Select By Attributes allows you to provide a SQL query expression that is used to select features that match the selection criteria Query-A request to select features or records from a database. A query is often written as a statement or logical expression. Fields-Tables form the foundation of geographic data and are the fundamental building blocks of any data model. Tables are a collection of information, such as a list of building owners, employees, or customer information. Layers in a map, such as city streets, buildings, or address points, are simply tables that include information about the geometry and location of those features. Records- Attributes-There are two components to GIS data: spatial information (coordinate and projection information for spatial features) and attribute data. Attribute data is information appended in tabular format to spatial features Relational Database-A data structure in which collections of tables are logically associated with each other by shared fields. Join Function-Joining data is typically used to append the fields of one table to those of another through an attribute or field common to both tables. You can choose to define the join based on either attributes or a predefined geodatabase relationship class or by location (also referred to as a spatial join). You will only see join by relationship class listed if you are joining geodatabase data for which a relationship class has already been defined in the geodatabase. Calculate/ Field Calculator-In some cases, you might want to perform a mathematical calculation to set a field value for a single record or even all records. You can perform simple as well as advanced calculations on all or selected records. In addition, you can calculate area, length, perimeter, and other geometric properties on fields in attribute tables NAD 1983 contiguous USA Albers- The Albers equal area conic is the typical projection for historical USGS maps of the lower 48, it being a general-purpose low-distortion compromise for mid-latitude short and wide extents.

Tuesday, March 21, 2017

Map Document: In ArcMap, the file that contains one map, its layout, and its associated layers, tables, charts, and reports. Map documents can be printed or embedded in other documents. Map document files have an .mxd extension. Table on Contents: a tabbed list of data frames and layers (or tables) on a map that shows how the data is symbolized, the source of the data, and whether or not each layer is selectable. Data Frame: A map element that defines a geographic extent, a page extent, a coordinate system, and other display properties for one or more layers in ArcMap. A dataset can be represented in one or more data frames. In data view, only one data frame is displayed at a time; in layout view, all a map's data frames are displayed at the same time. Many cartography texts use the term "map body" to refer to what ESRI calls a data frame. Map Layer: Layers are the mechanism used to display geographic datasets in ArcMap, ArcGlobe, and ArcScene. Each layer references a dataset and specifies how that dataset is portrayed using symbols and text labels. When you add a layer to a map, you specify its dataset and set its map symbols and labeling properties. Attribute Table: A database or tabular file containing information about a set of geographic features, usually arranged so that each row represents a feature and each column represents one feature attribute. In raster datasets, each row of an attribute table corresponds to a certain zone of cells having the same value. In a GIS, attribute tables are often joined or related to spatial data layers, and the attribute values they contain can be used to find, query, and symbolize features or raster cells.