Editing Geographic information system (section)

==Data output and cartography==
{{main | Cartographic design| Digital mapping}}
[[Cartography]] is the design and production of maps, or visual representations of spatial data. The vast majority of modern cartography is done with the help of computers, usually using GIS but production of quality cartography is also achieved by importing layers into a design program to refine it. Most GIS&nbsp;software gives the user substantial control over the appearance of the data.

Cartographic work serves two major functions:

First, it produces graphics on the screen or on paper that convey the results of analysis to the people who make decisions about resources. Wall maps and other graphics can be generated, allowing the viewer to visualize and thereby understand the results of analyses or simulations of potential events. [[Web Map Server]]s facilitate distribution of generated maps through web browsers using various implementations of web-based application programming interfaces ([[AJAX]], [[Java programming|Java]], [[Adobe Flash|Flash]], etc.).

Second, other database information can be generated for further analysis or use. An example would be a list of all addresses within one&nbsp;mile (1.6&nbsp;km) of a toxic spill.

An archeochrome is a new way of displaying spatial data. It is a thematic on a 3D&nbsp;map that is applied to a specific building or a part of a building. It is suited to the visual display of heat-loss data.

===Terrain depiction===
{{main | Terrain cartography }}
[[File:Swisstopo Eiger - Grindelwald.jpg|thumb|300px|A traditional topographic map rendered in 3D]]
Traditional maps are abstractions of the real world, a sampling of important elements portrayed on a sheet of paper with symbols to represent physical objects. People who use maps must interpret these symbols. [[Topographic map]]s show the shape of land surface with [[contour line]]s or with [[Cartographic relief depiction|shaded relief]].

Today, graphic display techniques such as [[shading]] based on [[altitude]] in a GIS can make relationships among map elements visible, heightening one's ability to extract and analyze information. For example, two types of data were combined in a GIS to produce a perspective view of a portion of [[San&nbsp;Mateo County]], [[California]].
*The [[digital elevation model]], consisting of surface elevations recorded on a 30-meter horizontal grid, shows high elevations as white and low elevation as black.
*The accompanying [[Landsat]] Thematic Mapper image shows a false-color infrared image looking down at the same area in 30-meter&nbsp;pixels, or picture elements, for the same coordinate points, pixel&nbsp;by&nbsp;pixel, as the elevation information.

A GIS was used to register and combine the two images to [[Rendering (computer graphics)|render]] the three-dimensional [[perspective view]] looking down the [[San Andreas Fault]], using the Thematic Mapper image pixels, but shaded using the elevation of the [[landform]]s. The GIS&nbsp;display depends on the viewing point of the [[observation|observer]] and time of day of the display, to properly render the shadows created by the sun's rays at that latitude, longitude, and time of day.

===Web mapping===
{{Main|Web mapping}}

In recent years there has been a proliferation of free-to-use and easily accessible mapping software such as the [[proprietary software|proprietary]] web applications [[Google&nbsp;Maps]] and [[Bing&nbsp;Maps]], as well as the [[free and open-source software|free and open-source]] alternative [[OpenStreetMap]]. These services give the public access to huge amounts of geographic data, perceived by many users to be as trustworthy and usable as professional information.<ref name = activities>{{cite journal|last1=Parker|first1=Christopher J.|last2=May|first2=Andrew J.|last3=Mitchell|first3=Val |title=The role of VGI and PGI in supporting outdoor activities|journal=Applied Ergonomics|date=2013|volume=44|issue=6|pages=886–94|doi= 10.1016/j.apergo.2012.04.013 |pmid=22795180|s2cid=12918341 |url=https://dspace.lboro.ac.uk/2134/10350}}</ref> For example, during the COVID-19 pandemic, web maps hosted on dashboards were used to rapidly disseminate case data to the general public.<ref name=Everts1>{{cite journal |last1=Everts |first1=Jonathan |title=The dashboard pandemic |journal=Dialogues in Human Geography |year=2020 |volume=10 |issue=2 |pages=260–264 |doi=10.1177/2043820620935355 |s2cid=220418162 |doi-access=free }}</ref>

Some of them, like Google Maps and [[OpenLayers]], expose an [[application programming interface]] (API) that enable users to create custom applications. These toolkits commonly offer street maps, aerial/satellite imagery, geocoding, searches, and routing functionality. Web mapping has also uncovered the potential of [[crowdsourcing]] geodata in projects like [[OpenStreetMap]], which is a collaborative project to create a free editable map of the world. These [[Mashup (web application hybrid)|mashup]] projects have been proven to provide a high level of value and benefit to end users outside that possible through traditional geographic information.<ref>{{cite journal|last1=Parker|first1=Christopher J.|last2=May|first2=Andrew J.|last3=Mitchel|first3=Val|title=User Centred Design of Neogeography: The Impact of Volunteered Geographic Information on Trust of Online Map 'Mashups|journal=Ergonomics|date=2014|volume=57|issue=7|pages=987–997|doi=10.1080/00140139.2014.909950|pmid=24827070|s2cid=13458260|url=https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/23845/3/Parker%2c%20May%2c%20Mitchell%20-%202014%20-%20User-centred%20design%20of%20neogeography%20the%20impact%20of%20volunteered%20geographic%20information%20on%20users%27%20perception.pdf |archive-url=https://web.archive.org/web/20170830034140/https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/23845/3/Parker%2c%20May%2c%20Mitchell%20-%202014%20-%20User-centred%20design%20of%20neogeography%20the%20impact%20of%20volunteered%20geographic%20information%20on%20users%27%20perception.pdf |archive-date=2017-08-30 |url-status=live}}</ref><ref>{{cite journal|last1=May|first1=Andrew|last2=Parker|first2=Christopher J.|last3=Taylor|first3=Neil|last4=Ross|first4=Tracy|title=Evaluating a concept design of a crowd-sourced 'mashup' providing ease-of-access information for people with limited mobility|journal=Transportation Research Part C: Emerging Technologies|date=2014|volume=49|pages=103–113|doi=10.1016/j.trc.2014.10.007|doi-access=free|bibcode=2014TRPC...49..103M }}</ref>

Web mapping is not without its drawbacks. Web mapping allows for the creation and distribution of maps by people without proper cartographic training.<ref name="Plewe1">{{cite journal |last1=Plewe |first1=Brandon |title=Web Cartography in the United States |journal=Cartography and Geographic Information Science |date=2007 |volume=34 |issue=2 |pages=133–136 |doi=10.1559/152304007781002235|bibcode=2007CGISc..34..133P |s2cid=140717290 }}</ref> This has led to maps that ignore cartographic conventions and are potentially misleading, with one study finding that more than half of United States state government COVID-19 dashboards did not follow these conventions.<ref name=Adams1>{{cite journal |last1=Adams |first1=Aaron |last2=Xiang |first2=Chen |last3=Weidong |first3=Li |last4=Zhang |first4=Chuanrong |title=The disguised pandemic: The importance of data normalization in COVID-19 web mapping |journal=Public Health |date=May 2020 |volume=183 |issue=3 |pages=36–37 |doi = 10.1016/j.puhe.2020.04.034|pmid=32416476 |pmc=7203028 }}</ref><ref name="Adams2">{{cite journal |last1=Adams |first1=Aaron M. |last2=Chen |first2=Xiang |last3=Li |first3=Weidong |last4=Chuanrong |first4=Zhang |title=Normalizing the pandemic: exploring the cartographic issues in state government COVID-19 dashboards |journal=Journal of Maps |date=27 July 2023 |volume=19 |issue=5 |pages=1–9 |doi=10.1080/17445647.2023.2235385|bibcode=2023JMaps..19Q...1A |doi-access=free }}</ref>