AMW contains world coverages of various themes, derived and
re-processed from the US Geological Survey (USGS) Vector Map Level 0
and the National Imagery and Mapping Agency (NIMA) Digital Chart
of the World. Most of the important themes from this source have
been included in AMW, while allowing the full database to be
contained on a single CD. The data is easily viewable using the
AGIS for Windows software, and AGIS can also be used to selectively
extract or export portions of the full data set.
The AMW database provides worldwide coverage at a nominal scale of 1:1,000,000. It consists of vector-based polygon, line and point data. Polygon and line data are organized into 10 thematic layers containing information on political boundaries, ocean depth contours, coastlines, land elevation contours, inland water bodies, built-up areas, rivers, major roads and railways, utility transmission lines and pipelines. A thematic layer of vegetated areas is also included for North America. Point data is included for names of countries (274 points), administrative areas (e.g. US states) (132), populated places (90,836), airports (12,373), deserts (143), inland waters (28,198), islands (7,418), mountains (3,915), cultural landmarks (207), ocean features (2,563) and land features (6,165).
US Military documentation for the data states that the absolute horizontal accuracy is 4,270 meters at 90% circular error for some information, and that vertical accuracy is +-152.4 meters for land elevation. This means that the data is not suitable for position critical purposes such as navigation.
Each map theme layer may contain more than one type of feature, each identified
by a feature type code (a number between 1 and 100). Display attributes are set according to the feature
code, and it is also possible to extract data from a theme for individual
feature types. A list of all map feature types found in each
theme layer included on the CD is as follows:
amwbor - border line features
2 country and state borders
62 cliff lines
amwbui - built-up areas
10 built-up areas
amwcoa - land areas
3 land areas
amwdep - depth contour lines and sea ice areas
51 200m
52 600m
53 1000m
54 2000m
55 4000m
56 6000m
57 8000m
61 sea ice areas
amwele - land elevation contour lines
20 <0m (<0ft)
21 152m (500ft)
22 305m (1000ft)
24 610m (2000ft)
26 1219m (4000ft)
28 1829m (6000ft)
30 2438m (8000ft)
32 3048m (10000ft)
34 3658m (12000ft)
36 4267m (14000ft)
38 4877m (16000ft)
40 5486m (18000ft)
42 6096m (20000ft)
44 6706m (22000ft)
amwlak - inland water and land ice areas
9 inland water
60 land ice
amwriv - rivers, streams and canal lines
5 permanent rivers and streams
6 intermittent rivers and streams
7 canals
8 miscellaneous hydrological lines
amwsho - land shore lines
4 shore lines
amwtra - transport lines
11 railways
12 major roads
13 trails and minor roads
14 transport structures (e.g. bridges, tunnels)
15 miscellaneous transport lines
amwuti - utility lines
16 pipe lines
17 transmission lines (e.g. electricity, phone)
amwveg - vegetated areas (North America only)
70 trees
71 tundra
72 crops
73 grass
74 swamp
Most important feature types were extracted and translated from the
VMAP0 source. To allow the information to fit on a single CD, the
largest omission was land elevation contours for heights between
the 2000ft contours. The original data is collected using a contour
interval of 1000ft. Where a feature type has been included, we have
endeavored to keep the resolution the same as the original - e.g.
each line feature should have at least the same number of points as
the same feature in VMAP0.
Additional processing was carried out to enable the data to be plotted
using AGIS. The first difference with VMAP0 data is that no single line or
polygon contains more than 2000 points. This is to enable users of
the 16 bit version of AGIS to use AMW. Also, VMAP0 may contain many
holes in individual polygons which may represent, for example, islands
in a lake. These holes were joined to the outer polygon in
such a way that a single polygon results, with no holes. For a number
of polygons in VMAP0, there were erroneous associated internal lines
which have been deleted in AMW. VMAP0 did not have coastline polygon
data for northern Norway. This has been corrected in AMW.
There are a number of errors in the VMAP0 set which have not been
corrected in AMW. The most obvious relate to the depth contours. There
is missing depth information for a large area near northern Japan, and
some details missing off southern Australia. Also, the polygon coast
layer does not contain a number of small islands which do appear in the
shore line layer. Land elevation lines are incomplete. In many areas
it is not possible to convert elevation lines into polygons due to
missing information. In the name data, misclassifications exist - for
example, some ocean features are classified as populated places. The
accuracy of name information is unknown, and should not be treated
as definitive.
As the CD contains an extremely large amount of information, plotting
displays directly from the CD may take some time - mostly dependent on
you CPU and CD drive speeds. It is, of course, possible to use AGIS to
extract subsets of data from the CD to you hard disk for more rapid
display and use in combination with your own data.
