GIS Dictionary

[computing] A keyboard shortcut that allows a user to access the contents of the Main menu by holding down the Alt key and pressing the underlined letter on the menu … Read more

1 [business] An aggregate measure of the degree of ease with which a place, person, or thing can be reached, depending on factors such as slope, traffic, distance, and so … Read more

[mathematics] The degree to which a measured value conforms to true or accepted values. Accuracy is a measure of correctness. It is distinguished from precision, which measures exactness.

1 [ESRI software] Circles, lines, polygons, points, or markers that become transparent when not active. Acetate features are overlaid on other map layers and can be independently annotated. 2 [cartography] … Read more

[ESRI software] In ArcGIS, an XML file that contains an acknowledgement message.

[ESRI software] In ArcGIS, a message from a replica to its relative acknowledging the data changes received by the sending replica.

[programming] Acronym for access control list. A list of accounts or users used to designate restricted and unrestricted services and the authentication criteria required to access an object.

[remote sensing] A remote-sensing tool with an oscillating mirror that moves back and forth across a satellite’s direction of travel, creating scan line strips that are contiguous or that overlap … Read more

[ESRI software] The data frame currently being worked onfor example, the data frame to which layers are being added. The active data frame is highlighted on the map, and its … Read more

[ESRI software] In Survey Analyst for field measurements, the focus of the analyses applied. In an active network, users may list a network’s datum points in the Survey Explorer, detect … Read more

[remote sensing] A remote-sensing system, such as radar, that produces electromagnetic radiation and measures its reflection back from a surface.

[ESRI software] In ArcView 3.x, the theme in a view document to which button and tool actions or corresponding menu commands are applied. An active theme appears raised in a … Read more

[non-ESRI software] A type of ArcIMS Application Server Connector that is a Component Object Model (COM) dynamic link library (DLL) which can be used in a COM application such as … Read more

[photogrammetry] A measure, using a microdensitometer or other instrument, of how well a photographic system shows sharp edges between contiguous bright and dark areas.