Editing Geological map (section)

== Maps and mapping around the globe ==
[[Image:North america terrain 2003 map.jpg|thumb|Geological map of [[North America]] superimposed on a [[Terrain cartography#Shaded relief|shaded relief]] map]]

===Singapore===
The first geological map of Singapore was produced in 1974, produced by the then Public Work Department. The publication includes a locality map, 8 map sheets detailing the topography and geological units, and a sheet containing cross sections of the island.

Since 1974, for 30 years, there were many findings reported in various technical conferences on newfound geology islandwide, but no new publication was produced. In 2006, Defence Science & Technology Agency, with their developments in underground space promptly started a re-publication of the Geology of Singapore, second edition. The new edition that was published in 2009, contains a 1:75,000 geology map of the island, 6 maps (1:25,000) containing topography, street directory and geology, a sheet of cross section and a locality map.

The difference found between the 1976 Geology of Singapore report include numerous formations found in literature between 1976 and 2009. These include the Fort Canning Boulder Beds and stretches of limestone.

===United Kingdom===
The [[United Kingdom]] and [[Isle of Man]] have been extensively mapped by the [[British Geological Survey]] (BGS) since 1835; a separate Geological Survey of Northern Ireland (drawing on BGS staff) has operated since 1947.

Two 1:625,000 scale maps cover the basic geology for the UK. More detailed sheets are available at scales of 1:250,000, 1:50,000 and 1:10,000. The 1:625,000 and 1:250,000 scales show both onshore and offshore geology (the 1:250,000 series covers the entire UK [[continental shelf]]), whilst other scales generally cover exposures on land only.

Sheets of all scales (though not for all areas) fall into two categories:

# [[Superficial deposits|Superficial deposit]] maps (previously known as ''solid and drift'' maps) show both bedrock ''and'' the deposits on top of it.
# [[Bedrock]] maps (previously known as ''solid'' maps) show the underlying rock, without superficial deposits.

The maps are superimposed over a topographic map base produced by [[Ordnance Survey]] (OS), and use symbols to represent fault lines, strike and dip or geological units, [[borehole]]s etc. Colors are used to represent different geological units. Explanatory booklets (memoirs) are produced for many sheets at the 1:50,000 scale.

Small scale [[thematic map]]s (1:1,000,000 to 1:100,000) are also produced covering [[geochemistry]], [[gravity anomaly]], [[magnetic anomaly]], [[groundwater]], etc.

Although BGS maps show the British [[Ordnance Survey National Grid|national grid reference system]] and employ an OS base map, sheet boundaries are not based on the grid. The 1:50,000 sheets originate from earlier 'one inch to the mile' (1:63,360) coverage utilising the pre-grid Ordnance Survey One Inch Third Edition as the base map. Current sheets are a mixture of modern field mapping at 1:10,000 redrawn at the 1:50,000 scale and older 1:63,360 maps reproduced on a modern base map at 1:50,000. In both cases the original OS Third Edition sheet margins and numbers are retained. The 1:250,000 sheets are defined using lines of latitude and longitude, each extending 1° north-south and 2° east-west.

===United States===
[[File:Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 77) (cropped).jpg|thumb|right|Geological Map of Ohio from "Geography of Ohio", 1923]]

In the [[United States]], geological maps are usually superimposed over a [[topographic map]] (and at times over other base maps) with the addition of a color mask with letter symbols to represent the kind of [[geologic unit]].  The color mask denotes the exposure of the immediate [[bedrock]], even if obscured by soil or other cover.  Each area of color denotes a geologic unit or particular [[rock (geology)|rock]] formation (as more information is gathered new geologic units may be defined).  However, in areas where the bedrock is overlain by a significantly thick [[unconsolidated]] burden of [[till]], [[Terrace (geology)|terrace sediments]], [[loess]] deposits, or other important feature, these are shown instead. [[Stratigraphy|Stratigraphic]] contour lines, [[Fault (geology)|fault]] lines, strike and dip symbols, are represented with various symbols as indicated by the map key. Whereas topographic maps are produced by the [[United States Geological Survey]] in conjunction with the states, geological maps are usually produced by the individual [[States of the US|states]].  There are almost no geological map resources for some states, while a few states, such as [[Kentucky]] and [[Geologic map of Georgia|Georgia]], are extensively mapped geologically.