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Base Maps, Data or Layers
base maps, data, or layers - Spatial data sets that provide the background upon which more specific thematic data is overlaid and analyzed.


Base Map
A map containing geographic features, used for locational reference.

Base Map layers are designed to contain pre-authored content, such as rasters or imagery. As a trade off for enhanced drawing and rendering performance, most geoprocessing tools cannot be used on Base Map layers.

Base Map: The term 'base map' is used, throughout this site, to signify those GIS cartographies which chart a writer's movement through place over time. In other words, the 'base map' indicates where a writer claims that he was situated on a particular day in history.

Base Map: Map on which information would be placed for purposes of comparison. It may be used to construct other maps by the addition of information. Base maps usually contain mapped data that seldom changes and is used repeatedly.

~: A term which varies in different applications, but, in general, refers to a map that depicts the fundamental map elements, such as streets, buildings, streams, etc., which are used frequently for locational reference.

~s provide the background upon which thematic data is overlayed and analyzed.

~ A map containing visible surface features and boundaries, essential for locating additional layers, or types, of georeferenced information.

~s
The spatial models are developed from geographic information. We used a popular desktop GIS (geographic information system) to house the spatial database. We geocoded each customer's address and the location of our store.

~
A map which displays planimetric and /or topographic information and which may be used as a base for a thematic layer. Features which may be included on a ~ are: roads, rivers, major structures (buildings), contours, etc. Feature presentation will, however, be map scale dependent.

~ or Base Layer
The foundation of a GIS on which all other data layers are built. The accuracy of the ~ dictates the accuracy of other data used in the GIS. Digital orthophotography is a commonly used ~ for counties and cities.
COGO ...

~s

~s depict fundamental information about the Earth's surface such as landforms and drainage. They also symbolize landmark features like roads, railways, populated places and buildings.

~: A map containing the background upon which geographic data is overlayed and analyzed. Basic representation of a region of the earth as it would appear if viewed from above. Portrays basic reference information onto which other information of a specialized nature is placed.

~
Basic representation of a region of the earth as it would appear if viewed from above.
Portrays basic reference information onto which other information of a specialized nature is placed. Usually shows the location and extent of natural earth surface features and permanent man-made objects.

~, bearing, buffer.
- C -
Cadastral, cardinal points, coordinates, coverage.

~ - In a GIS or digital mapping system, ~ refers to those layers of map information (e.g. topography, roads, rivers and lakes) used for georeferencing layers of thematic information (e.g. forest stands, mineral deposits, land use and population distribution).
...

~
A map designed specifically to be used as a template, onto which further information is placed for the purpose of comparison or spatial correlation. ~s are often simple outline maps and are usually devoid of any information deemed unnecessary for basic geographical reference.

~ printed in a dark colour (usually black or sepia)
The addition of colour by hand painting (it is interesting to note that, in haste, the artist painted the land as well as water areas around Adelaide.

~s showing reporting zones
atlases produced for urban areas
digital products - boundary files, TIGER
E. TIGER ...

parcel-~ A map showing land parcels that is used as the fundamental data layer to which other data layers are referenced.
parcel-based GIS A GIS with data organized with a land parcel ~ as the fundamental data layer to which other data layers are referenced.

Ontario ~; Ontario Basic Mapping Program
OBRP
Object representation ...

Figure 3. ~ produced in ARC/INFO with 1962 aerial photograph showing the study area.
...

Then on the ~, over the streets and fatalities, he drew the locations of water wells. Familiar with the idea of distance decay, he knew that people might go a far distance to purchase a product that was cheaper, but they would go to the nearest well because water was free and heavy to carry.

~: A set of topographic data displayed in map form providing a frame of reference or contextual information to the user.
Buffer: A polygon enclosing an area within a specified distance from a point, line or polygon.

~ A map showing planimetric, topographic, geological, political and/or cadastral information that may appear in many different types of maps. The ~ information is drawn with other types of changing thematic information.

~s, data, or layers Spatial data sets that provide the background upon which more specific thematic data is overlaid and analyzed.

~ See: map, base. bathymetric map See: map, bathymetric bathymetry Science of measuring water depths (usually in the ocean) to determine bottom topography.

~ for Property Data - When collecting information on property boundaries, use the best ~ available. USGS 1:24,000 scale "quads" often work well in rural areas, road maps can be used in urban places.

About Contextual ~s
U.S Data available on the GSD LAN
World-Wide Data Sources on the GSD LAN
Exporting Shapefile Data and Layer Information
Choosing a Projection ...

The term "~" was at one time applied to a class of maps now known as outline maps. It may be applied to topographic maps, also termed "mother maps" that are used in the construction of other types of maps by the addition of particular data.

If the user selects the SCREEN option, then points marked on the image will automatically be associated with the coordinates from the corresponding points on the target data ~ layer.

Using a GIS and digital versions of the 1:100,000 - scale transportation network, political boundaries, and hydrographic features, cartographers produced a 1:500,000 - scale standard ~ of New Jersey.

Both provincial governments have defined and implemented province wide coverage of digital ~ data at varying map scales, e.g. 1:20,000 and 1:250,000. As well, the provincial forestry agencies also provide thematic forest inventory data in digital format.

We (designers) then take the ~s and either leave what they showed or draw over it with actual pipes and structures. Depending on our scenario whether we have profiles, cross sections and such, will dictate what avenue we need to go down.

Starting with an accurate ~ of a London neighborhood which included streets and pump locations, Snow mapped out the incidents of cholera death. The emerging pattern centered around one particular pump on Broad Street.

The maps created using parcel mapping services comprise of polygons which are created from the ~, which shows the details of the ownership of the properties and related information.

You'll need to match the coordinate system of the ~ you choose to use, whether it is ArcGIS Online, Microsoft Bing Maps, or Google Maps. All of these online maps are stored with a continuous tiling system to support the seamless display of map data for large scale subareas (e.g.

If an image is not geometrically distorted in any way (not rotated, not skewed, not in a mountain area, etc) as compared to the ~, than a one step geo-referencing may work.

A general 3D model of whole city territory was created from the 2D ~ database, city's building cadastre and orthophotos.
The accurate 3D city model, which is replacing the digital 1:500 ~, is expanding constantly and is used in many city planning and construction projects.
Full story ...

The DRGs now serve a major role as a complete ~ for use within the SJRWMD's GIS.
Thanks to Brian May of the SJRWD for this contribution. All rights reserved - This article is the property of the SJRWMD and has been provided by them to The GeoCommunity.

DATA COLLECTION AND TRANSFORMATION STANDARDS
geodetic control, locational accuracy, ~
coordinate-reference system
mapping scale, resolution
data content, completeness
classification system, coding methodologies
digitizing-automation techniques (image
processing) ...

* In order to save time, and maintain accuracy, the proceedure is to use the same coordinate grid system as the ~ or GPS system used in the collection of ground control points.

[ESRI software] A Web-based system for sharing, finding, and using maps, layers, and services. ArcGIS Online includes a set of ~s, map layers, and tools published by ESRI for use inside ArcGIS products.

Components would include e-mail, access to data archives, presentation of parallel texts and counter texts in diverse media, real-time data analysis, standard ~s and data sets, sketch map and field note capabilities (Schroeder, 1995).

The chapter also includes descri ptions of several types of projections for use when mapping various areas, such as the Mollweide, Hammer, Bonne, Alber's equal area, Lambert's conformal conic and more. The second half of the chapter is devoted to ~ compilation.

Removing information related to ~ features (e.g., state boundaries on a US map) or readily identifiable features (e.g., highway or interstate symbols) is one effective way to minimize legend size.

These range from simple programs that facilitate the keyboard entry of survey co- ordinates to techniques that reconcile aerial photographs with ~s. Photogrammetric, remotely-sensed and CAD-generated data represent yet further potential input sources.

GIS standards categories COMPUTING STANDARDS hardware software data formats communications (cabling, network protocols) DATA COLLECTION AND TRANSFORMATION STANDARDS geodetic control, locational accuracy, ~ coordinate-reference system mapping scale, resolution data content, ...

See also: See also: What is the meaning of Map, Information, GIS, Geographic, Location?

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