This map shows the results of the search you defined on the data
search page, either as
Pins or
Polygons depending on the
selections you made. You can manipulate the results at this
stage in a number of different ways. Before drawing any
conclusions from your results, you should read the important
Health Warning at the
bottom of this page.
Choosing a Base Map
In the upper right hand corner of the map you will find a pull
down menu. The default setting is
1746. Leaving this
unchanged will result in your data being mapped on to
John Rocque's map of London
of that date. But you can choose from five different
alternatives:
-
1746: John Rocque's map
of London. Go to
Background information on this map.
-
1869-80: This selection
will display your results over the first Ordnance Survey map
considered fully geographically accurate - that first
published between 1871 and 1880.
Background information on this map. As the data available for mapping derives from the period
before 1819, using this base map runs the danger of
misrepresenting the urban character of the areas involved, but
fully and accurately reflects the underlying geography of the
region. Many of the borders used in defining parishes and
wards were also taken from this late nineteenth-century map.
-
Blank:Using a
Blank map will
highlight the relationship between different elements of data,
and is particularly useful for viewing the colour shading of
polygons when you wish to explore the spatial distribution of
events or information.
-
Map: This selection
allows you to display your data over a modern schematic map of
Greater London, derived from
Google Maps.
-
Satellite: This will
display your data over a photographic satellite image of
modern London drawn from Google Earth.
The normal mouse commands for
Google Maps and
Google Earth work with
this site; so you can zoom in using the icon in the upper left
hand corner of the map, or by using your mouse wheel. You can
also drag the map by left-clicking your mouse.
Data Boxes
Every time you use a
Data search form to
select new data, a new box will appear on the map page,
displaying the data you have selected. The tick box in the upper
left hand corner of the
Data Box allows you to
toggle on and off that particular set of data. The colour key
for that data set is displayed in the upper right hand corner.
The pull-down menu in the
Data Box allows you to
decide how to display your results - as, for instance,
pins or
polygons. See
Display As below, for
further details on this function. Directly below the
Data Box,
Add Data allows you to
select an additional dataset to display on your map. There is no
functional limit to the number of datasets you can map in this
way. Reset view returns
the map to the default scale.
Display As
In the Data Box you will
find a pull-down menu that allows you to select how you wish to
Display your results. The
most appropriate display format depends on the nature of the
data you have selected. The pull-down menu includes the
following choices:
-
Polygons: A polygon is
simply a bounded shape such as a square or triangle. In this
context polygons can be
parishes,
wards, or other types
of place such streets.
The polygons dispayed on the map are determined by how you
grouped your results on
the data search form. For instance, if you grouped by
Parish, polygons
representing the parishes of London will be displayed on your
map.
-
Polygons (no border):
As with a simple
polygon this display
format divides your data between defined areas, but does not
mark out their borders. This is particularly useful when
exploring the distribution of densities (of crime or
population for example) across space, and should normally be
used with a blank base
map.
-
Pins (per hit): This
will display each
hit as an individual
pin. This is
particularly useful when mapping a relatively small number of
hits (under
approximately 500).
-
Pins (grouped): This
will display your
hits as pins, but
collect them according to type of place you have
grouped by (such as
parish), with the number of hits reflected in the size of the
pin displayed. So, for
instance, if there are 20 hits for 'St Dionis Backchurch' and
two hits for 'St Botolph Aldgate', the pin for the St Dionis
will appear substantially larger. This format is useful when
displaying larger amounts of data.
-
Polygons Adjusted by Area: This selection divides the number of hits for each
polygon by its area on
the map, with the shading reflecting the density of hits. This
is particularly useful when comparing results for the large
extra-mural parishes of Westminster and Middlesex with those
from the small parishes of the City of London.
-
Polygons Adjusted by Area (no border): As with a simple
Polygon Adjusted by Area
this display format divides your data between polygons divided
by area, but does not mark out borders. It is particularly
useful when exploring the distribution of densities (of crime
or population for example) across space, and should normally
be used with a
blank base map.
-
Pins adjusted by Area:
This will display your
hits as pins, but
collect them according to type of place you have
grouped by (such as
parish), with the size of the pin determined by the number of
hits divided by area.
The relative density of
hits will be reflected
in the size of the
pins displayed.
-
Small Blocks: This
display format divides the whole map surface into square
blocks and displays the relative density of
hits per block. This is
particularly useful when using data which includes different
types of place names (such as parishes and street names),
since every hit is included. Where a place covers more than
one block, the hits are divided proportionally into each
block. Small Blocks are
particularly useful when exploring the geographical
distribution of densities for data that is not dependent on
parish administration.
-
Large Blocks: This
display format divides the whole map surface into larger
blocks and displays the density of
hits per block.
Large Blocks are
particularly useful when exploring the geographical
distribution of densities for data relating to large regions
in London such as when comparing the west end with the east
end.
Reading the Colour
Density Range
When you map data as
polygons it will be
displayed as increasingly dense colour blocks, from, for
instance, transparent to dark blue. Although the human eye
cannot distinguish more than five shades of colour, the results
are a continuum of shading. By selecting
Disregard This Place from
the data balloon accessed by left clicking a polygon, you can
eliminate that polygon's data from the calculation used to
determine the shading of the map as a whole. This is
particularly useful when anomalous results for a few locations
make it difficult to distinguish differences on the rest of the
map. Using a Blank base
map, selected from the upper right hand menu, will make the
depth of shading stand out more clearly.
Left Button
Functionality
You can access detailed information and more functions by
Left Clicking your mouse
over any Polygon or
Pin. This will bring up a
balloon displaying the name of the
Place on the map (whether
a parish, ward, or street) and the number of records associated
with that Place from the
data you selected. You also have the option to
Show the data. Selecting
this option will take you back to the
Data page (you can
navigate back to the map by clicking on the
Map tab in the upper
right hand of the page). The balloon may also contain
information about how the data have been
Grouped. Finally, at the
bottom of the balloon you are given the option to
Disregard This Place (you
may need to use the scroll bar in the balloon). See
Reading the Colour Density Range.
Accuracy and
Interpretation: Important Health Warning
The value of your results depends entirely on the accuracy of
the underlying data. Each dataset has its own limitations
concerning the accuracy and thoroughness of the place name
information provided, so you should familiarise yourself with
the original dataset before drawing any conclusions. See the
Historical Background pages
for information about each dataset, and links to further
information. In addition, the process of geo-coding place name
information to enable it to be mapped is subject to a degree of
error.
In particular, you should be aware of the following potential
sources of error:
-
Were place names regularly provided in the original source? If
not, as is the case with defendant homes in
Old Bailey trials, the
results will be incomplete.
-
Do data survive for all of London? Several parishes are
missing, for example, from the
Four Shillings in the Pound
tax.
-
Were place names in the original text consistently marked up
as such in the electronic edition? Place names in
London Lives, for
example, were mostly tagged using an automated process, which
was subject to a degree of error. For more information, see
that project's
About this Project
page.
-
Does the dataset contain a mixture of different types of place
name information? Several
London Lives document
types, such as the
Minutes of the Court of Governors of Bridewell, include information about a mixed group of individuals, in
this case petty criminals, apprentices and governors. It may
be possible to filter out irrelevant data by adding keyword(s)
to your search criteria or by using the
disregard this place
feature discussed above (under
Reading the Colour Density Range). Alternatively, you can export the data and edit the
results in a spreadsheet.
-
What proportion of the place names in the data have been
successfully mapped? As explained on the
Geocoder
background information page, many place names could not be
successfully geo-referenced, because the information is
incomplete, ambiguous, or the place name does not appear on
contemporary maps. The
Data search results
pages indicate the proportion of the first 200 results for
your search which could be mapped. By clicking on
Show more hits you can
page through the data to see the success rate for additional
groups of 200 hits.
Citing Your Results
If you wish to use a map generated by this website in your
research, you need to include a citation which documents the
process by which the map was compiled. For advice on this, how
to cite material from this website more generally, and see our
terms of use, see our
Copyright and Citation Guide.