It has a built year, the number of floors, etc. Those are attributes. Attributes are the facts we know, but not visible such as the built year. It can also represent the absence of a feature. Usually, a table helps to display attribute data. Each row represents a single feature. In a GIS, clicking on the row will highlight the corresponding feature on the map. Spatial data consists of points, lines, polygons or other geographic and geometric data primitives that we can map by location.
It is possible to maintain spatial data as vector data or raster data. Each provides information connected to geographical locations. Vector data consist of sequential points or vertices to define a linear segment. It has an x coordinate and a y coordinate. Furthermore, raster data consists of a matrix of cells or pixels arranged into rows and columns.
Spatial data can have any amount of additional attributes accompanying information about the location. Each of the buildings, in addition to their location, may have additional attributes such as the type of use housing, business, government, etc.
To identify exact locations on the surface of the Earth, a geographic coordinate system is used. Normally, an x and y-axis are used in mathematical systems, but in geography, the axes are referred to as lines of latitude horizontal lines that run east-west and longitude vertical lines that run north-south.
Georeferencing and geocoding are different but similar processes since both involve fitting data to the appropriate coordinates of the real world. The data used in geocoding are addresses and location descriptors city, country, etc. Each of these locations is given the exact coordinates of reference for that location on the surface of the Earth. The most common way that spatial data is processed and analyzed is using a GIS, or, geographic information system.
These are programs or a combination of programs that work together to help users make sense of their spatial data. This includes management, manipulation and customization, analysis, and creating visual displays. A user will typically use multiple spatial datasets at one time and compare them or combine them with one another.
Each spatial dataset may be referred to as a layer. If you were using GIS for a municipality project, you might have vector data like street data lines , neighbourhood boundary data polygons , and high school locations points. Each dataset would exist as its own layer in your GIS. Placement of layers is important for visual purposes as it will help you understand the various types of data and present your findings in an easily understandable way.
In this case, you would want to make sure that high school points and street lines are layers above neighbourhood boundaries. Otherwise, you would not be able to see them. The field and study of GIS extends much further than digital mapping and cartography. It consists of a variety of categories including spatial analysis , remote sensing, and geovisualization.
In these GIS fields, the spatial data becomes much more complex and difficult to use. In addition to raster and vector data, there is also LiDAR data also known as point clouds and 3D data. LiDAR data is data that is collected via satellites, drones, or other aerial devices. Maps are a common practice of presenting spatial data as they can easily communicate complex topics.
They can help validate or provide evidence for decision making, teach others about historical events in an area, or help provide an understanding of natural and human-made phenomena.
When creating visuals, graphics, or maps with spatial data, there are a variety of geographic elements to consider. One of the most important and coincidentally most problematic elements is projection. Numeric values will be sorted in sequentially either in ascending 1 to 10 or descending 10 to 1 order. Numerical value fields can have operations performed such as calculating the sum or average value.
Numerical field values can be a count e. BLOB stands for binary large object and this attribute type is used for storing information such images, multimedia, or bits of code in a field. This field stores object linking and embedding OLE which are objects created in other applications such as images and multimedia and linked from the BLOB field.
What is GIS? Types of Attribute Data Attribute data can be store as one of five different field types in a table or database: character, integer, floating, date, and BLOB. Character Data The character property or string is for text based values such as the name of a street or descriptive values such as the condition of a street.
Numeric Data Integer and floating are numerical values see: the difference between floating and integer values.
BLOB Data BLOB stands for binary large object and this attribute type is used for storing information such images, multimedia, or bits of code in a field.
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