Ground surveying involves a person or mechanism that observes or interacts with people or the environment in a particular place. Two main methods of spatial data collection, or gathering information about places, are ground surveying and remote sensing. A third important piece, not shown, is the time at which these data were collected. The table and map represent two key elements of spatial data: location and attributes. This attribute table and linked map show state boundaries with data from the U.S. In the case of the states, we could be concerned with population or income or any of hundreds of other characteristics.ĭata table and map. Finally, attribute characteristics describe the nature of a location. Temporal characteristics refer to how data represent a “snapshot” of what things were like at the time the data were collected, such as census data from the year 2000. More broadly, spatial information can take the form of a street address, latitude-longitude coordinates, or the area in which data was collected (e.g., residential block, city, state, country). Spatial characteristics of data, namely location of state boundaries, are necessary to put the data on a map or use.
Spatial – where an object is located or an event has occurred.Resolution, accuracy, and interoperability – important concepts that are part of metadata and are important to keep in mind when choosing appropriate data for a project.īy the end of this chapter, you should be able to ask thoughtful questions about the data used in mapping. How data in the US census – a survey that underlies many of the examples and activities in this book – are collected and aggregated.Elements and common types of spatial data.Instead, we focus on how and why data were collected for what, where, and when.
These data are necessarily just a small portion of what can be measured because it is impossible to measure all characteristics for all places for all times. An individual or group of people has asked one or more questions, gathered data in response, and processed the raw numbers before putting it all on the map. When admiring a well-designed map, it is easy to forget that it is made from data that came from somewhere.
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