Transcript APRS-IS - Red Sword

Maps for APRS
John Beadles, N5OOM
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Purpose of this Presentation
• This presentation is an introduction to the topic of
digital map data
• I’m still working on this presentation, so it’s a little
scattered and there are some holes
• This topic is waaay too big to be contained in a 1
hour presentation
• But hopefully this will get you started!
• If you want to know precisely how to get maps into
your APRS software, you need to refer to the
documentation for your application
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Topics
In this presentation, we will cover:
• Types of digital maps
• Coordinates
• Types of Maps
– Vector Maps
– Raster Maps
• Map types used by various APRS Software
• Map Products useable for APRS
• Links to Online Resources
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Types of Digital Maps
•
Feature maps
– Roads, political boundaries, utilities, hydrology, digital elevations, etc.
– Constructed from ground surveys, aerial and satellite photos
– Often one feature type per map data file (or “layer”)
•
Geoid Models
– Gravitational field map, used for high precision surveying, etc.
– Constructed by using aerial, satellite gravity surveys
•
Digital Elevation Models
– Model of the shape of the earth
– Used for RF propagation modelling, construction estimation, flood plain modelling
– Constructed by ground surveys, stereo aerial photo digitization, SARsat mapping
•
For the purposes of
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Coordinates
• Digital maps may use either of two types of
coordinates
– Latitude / Longitude
– Plane Coordinates
• Usually we’ll use Latitude and Longitude
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Latitude and Longitude
•
Latitude and Longitude (lats and lons) is a spherical coordinate system that is
intended to uniquely locate points on a round earth
•
Latitude is expressed as an angle from the equator.
– Latitude is zero at the equator, 90 degrees at the poles
– Lats in the northern hemisphere are expressed as positive or “north” value.
Lats in the southern hemisphere are expressed as negative or “south”.
– Example: +32.5000 or 32.5 degrees North
•
Longitude is expressed as an angle from an imaginary line (the prime meridian)
running through Greenwich, England
– Longitude is zero at the prime meridian and 180 degrees on the opposite
side of the earth
– Lons east of the prime meridian are positive or “east”, west of the prime
peridian are negative or “west”
– Example: -90.70 degrees or 90.70 degrees west.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Lats & Lons on the Earth
es
r e de
g
De gitu
n
Lo
+ 0 to 90 Degrees
Latitude
The Prime Meridian is a line
that runs from pole to pole
through Greenwich, England. It
is the line from which Longitude
is measured.
ees
Degr
0
8
1
+ 0 to ongitude
L
- 0 to 90 Degrees
Latitude
Degrees Latitude
s
egree
80 D
1
o
t
-0
itude
Long
Latitude is measured
from the equator, with
the equator being at 0
degrees.
Latitudes and Longitudes are
angles created from artificial
mathematical constructs that we
use to describe the shape of the
earth.
Any given point on the earth will
have a different latitude and
longitude depending on where we
say the center of the earth is, how
the axes are rotated and where
we say the prime meridian is.
The set of parameters that list this
information is called a DATUM.
There are many different datums
that have been used for specific
purposes. The Lat and Lon for a
place on the earth in one datum
may not be the same in another
datum.
The datum that is used by the
U.S. Navstar GPS system is
WGS-84, which is practically
interchangable with NAD-83
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Lat / Lon Conversions
•
For convenience sake, lats and lons may be expressed many different ways.
•
Decimal degrees is a common expression
– Example: 32.5250, -97.3250
•
APRS uses degrees and decimal minutes
– Example: 32 31.50N, 97 19.50W
– Convenient because a minute of angle is roughly 1 nautical mile
– Decimal degrees = dd + mm/60
– DD MM.mm = Int(DecDeg) and (mod(DecDeg))*60
•
Degrees, Minutes, Seconds is used to subdivide degrees down
– Example: 32d 31m 30s N, 97d 19m 30s W
– Decimal degrees = dd + mm/60 +ss/3600
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Datums
•
As we said, latitude and longitude are angles that are used to identify
unique locations on the world
•
But the lat and lon coordinate construct is a pure mathematical
construct that doesn’t have any particular relationship with the real
world
•
A datum is a set of definitions that tell us how lat and lon relate to the
real world. A datum defines the shape for the earth (the ellipsoid), the
origin of the coordinate system with respect to the center of the earth
and rotation vectors that describe how the coordinate system origin
matches to physical locations.
•
There are many datums that have been constructed to deal with many
local mapping issues. This happened a lot when computing power
was expensive or non-existent. With the advent of cheap computers
and GPS, the number of datums will probably narrow down, but there
are many historical datums out there.
•
Latitudes and Longitudes in one datum will not be equal to those in
another, and the difference isn’t necessarily constant
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Coordinate Conversion
•
Sometimes you might get map data in coordinates other than Lat / Lon or you might have to convert Lat /
Lon from one datum to another
•
Corpscon
– is a free MS Windows based conversion tool from the US Army Corps of Engineers
– http://crunch.tec.army.mil/software/corpscon/corpscon.html
•
Blue Marble Geographics
– Industry standard tools, but expensive
– http://www.bluemarblegeo.com/
•
Gpsinformation.net
– Has references to a lot of GPS data download tools
– http://gpsinformation.net/
•
Other times you might have to modify the format of GPS data to get it into a map.
– Often you can open GPS data files with a text editor (notepad, etc.)
– Some modification can be done with a spreadsheet
– For more extensive changes, the Perl language is a very powerful tool for doing data processing
– www.perl.org for www.activestate.com for MS Windows ports
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Datums for APRS
•
Generally speaking, american users will only be interested in a few.
•
The Navstar GPS system uses WGS-84 (World Geodetic System of 1984) as
its’ native system. The accepted civil datum for the United States is NAD-83
(North American Datum of 1983), which almost identical to WGS-84.
•
WGS-72 and WGS-64 were earlier attempts at a global datum. Neither are in
common use.
•
NAD-27 (North American Datum of 1927) is a very old regional datum. This
datum was defined by long distance surveys across the entire United States.
Accumulated error in the surveys resulted in a very non-linear expression of
Lats and Lons across the U.S.
•
Other countries use other datums
•
The higher the resolution your maps, the more important it is that your GPS is
set to the same datum as your maps. The difference can be thousands of
meters.
•
I can keep going on this subject for an hour alone, so we’re going to drop it
here.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Types of Maps
• Vector Maps
• Raster Maps
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Vector Map Characteristics
•
A vector map is a file of raw data
that a computer uses to draw a map
on demand
BEGIN LINE
32.744033,-96.894967
32.744033,-96.894833
•
Lines and other objects are defined
as coordinate pairs
•
Maps with unformatted text can be
pretty ugly
32.743883,-96.894767
Map features can be dynamically
edited
32.743700,-96.894700
Sometimes used with associated
database entries (Geographic
Information Systems)
32.743417,-96.894567
Includes Tiger data, USGS DLG
data used with some APRS
software
32.743000,-96.894417
•
•
•
32.743967,-96.894767
32.743933,-96.894767
32.743817,-96.894767
32.743567,-96.894617
32.743250,-96.894517
32.743100,-96.894483
32.742983,-96.894300
END
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Raster Maps
•
Is basically a picture
•
Accompanied with a file
containing associated
geographic information
096.47.216W,34.05.628N
096.46.154W,34.04.781N
2003 MS-150 Sun Lunch Stop
•
Features are drawn on and
cannot be easily modified
•
Often used as a base map on
which other features are drawn
•
.GIFs, .JPGs, GeoTiffs
•
Is the default map type used by
UI-View, can be used with
Xastir, WinAPRS
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Raster Map Example
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Map products useable for APRS
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Vector Data
•
Census Dept TIGER Data
•
Tiger data is complete, but quality
can be highly variable but is
updated regularly
•
USGS DLG (Digital Line Graphs)
are digitized versions of USGS
1:24000 maps, rarely updated
•
Commercial data is often Tiger
data that is formatted and cleaned
up – very expensive!
•
Some conversion software exists
to convert TIGER, DLG data to
WinAPRS / MacAPRS format
– Xastir
•
USGS Digital Line Graphs
•
WinAPRS / MacAPRS file format
– WinAPRS / MacAPRS
– UI-View
– Xastir
•
PocketAPRS file format
•
Commercial Data
– Used in MapInfo, AutoCad
– Would need to be converted to
proper format
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Consumer Software Products
•
Delorme StreetAtlas
•
Generally APRS software that uses a
consumer product doesn’t directly access the
data directly, it uses a programming interface
to talk to the mapping software, which does
what the APRS software wants it to do
•
Therefore, the APRS program is dependent on
the programming interfaces provided by the
map software. Not all map software provides
this interface.
•
Map data used in consumer map products is
virtually always proprietary – you aren’t allowed
to access or convert the raw data.
•
Most of these products are based on updated
TIGER data from the US Census Dept.
– APRS+SA
– UI-View (some versions of SA)
•
Precision Mapping
– UI-View
– WinAPRS
•
Microsoft MapPoint
– APRSPoint
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Web Based Products
• APRSWorld
• Tiger Map Server
• MapBlast
– JavAPRS
– Radio Mobile
• TerraServer
– UI-Terra
– Xastir
• Used to create a raster map
which you can then take with
you
• Can’t make new maps
unless you are connected to
the internet
• UI-Terra is downloadable
from the UI-View web site
• Radio Mobile is an RF
Propagation package that
can be used to make APRS
(UI-View) compatible raster
maps
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Scanned & Raster Maps
• GeoTIFFs
– Various sources
– WinAPRS / MacAPRS
– Xastir
• Digital Raster Graphics
• UI-View map format
– Graphic image & geoinfo
file
• GeoTiffs are a specific
image format that has
associated geographic
information associated with it
• Digital Raster Graphics are
scanned copies of USGS
1:24000 maps
• UI-View format is a .bmp or
.jpg with an associated text
file containing the lats and
longs of the upper left and
lower right corners.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
GIS Data
• Arcinfo Shape Files
– Xastir
• MapInfo
– Useable only after
conversion
• GIS data is generally vector
data that is formatted for a
particular industrial GIS
application
• ArcInfo shape files are
useable by some
applications
• Need to check copyright
information on the source
data.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Do It Yourself Data
•
May be needed to correct bad
map data
•
Collect with GPS
– Use within a mapping
program (such as a “draw
layer” in StreetAtlas
– Or save as a text file and
compile into a vector format
useable directly by a
program
•
Hand drawn
– Street Atlas provides a
function for drawing roads in
by map
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Manipulating data files
• If you have a GPS data file from some where, and it
won’t import, try opening it up in a text file.
• If the file isn’t full of binary data, save a clean copy
and then see what happens when you modify the
files
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Map File Formats
• GeoTiffs
• Xastir Pixmaps
• UI-View Image Files
• Street Atlas Draw Files
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
GeoTIFF
•
A GeoTIFF file is a TIFF image file with geographic information imbedded in the image
– The geographic image data file may be buried in the TIFF image file
– Or may be in a separate .FGD file
•
They are a standard in the GIS industry
•
However, TIFFs are generally high-resolution images and aren’t compressed, so they tend
to be very large
•
Sometimes they are available commercially
– Such as these canadian quad maps
– http://www.softmaptech.com/en/pages/geotiff_EN.html
•
Othertimes through government or public works sites
Minimum contents of a sample .FGD file
1.5.1.1 WEST BOUNDING COORDINATE: -122.000000
1.5.1.2 EAST BOUNDING COORDINATE: -120.000000
1.5.1.3 NORTH BOUNDING COORDINATE: 48.000000
1.5.1.4 SOUTH BOUNDING COORDINATE: 47.000000
Taken from: http://www.xastir.org/manual/sec_mapdetails.html
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Xastir Pix Map
.geo files can have many elements:
FILENAME filename
• Consists of two files
This specifies the filename of a map image to be loaded from the
local disk.
– A pixel map (.xpm)
– A geographic calibration file (.geo)
URL http://website
This specifies the URL of a map image to be loaded from a web or
ftp site. ImageMagick only.
TIEPOINT x-pixel y-pixel longitude latitude
Two tiepoints are required, and more than 2 will be ignored. these
two lines are for connecting an x,y pixel position in the image to a
lat and long position on the earth. The points should be as close as
possible to the upper left corner and the lower right corner of the
image for best accuracy.
Sample .geo file
FILENAME world1.xpm
IMAGESIZE pixels horizontally pixels vertically
# x y lon lat
This specifies the size of the image in pixels. If this is not set, the
image will be loaded each map redraw, regardless if it is on screen
or not.
TIEPOINT 0 0 -180 90
TIEPOINT 639 319 180 -90
DATUM datum
This feature is not implemented.
IMAGESIZE 640 320
PROJECTION projection
This feature is only partially implemented, default is "LatLon", other
possibility is "TM" to specify that the map is in Transverse Mercator
projection.
# anything Any line with the first character of a '#' will be ignored.
Taken from: http://www.xastir.org/manual/sec_mapdetails.html
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
UI-View Maps (from UI-Terra)
UI-Terra builds an area photo by
downloading photo tiles from
TerraServer and generates a text
.inf file containing the upper left and
lower right coordinates of the
image.
Sample .inf file
096.47.216W,34.05.628N
096.46.154W,34.04.781N
2003 MS-150 Sun Lunch Stop
The name that shows up
in UI-Views’ Maps list
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
UI-View Maps (from RadioMobile)
This map is a combination
of a digital terrain map and
a mapblast road map. This
map was exported with a
UI-View .inf geographic
information file.
Had we wished to do so,
we could have left the
terrain map blank so we
would just see the streets.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Street Atlas Draw Files
Sample StreetAtlas Draw File
•
•
Draw files allow Street Atlas users a way to
draw and save their own features in Street Atlas
BEGIN LINE
Each file consists of one or more files bounded
by a “BEGIN” and “END” keyword.
33.259649,-96.679974
33.259445,-96.680179
33.261023,-96.679923
33.264370,-96.679897
•
•
Each pair of coordinates represents a vertex in
a line segment.
END
BEGIN LINE
33.275828,-96.679693
– HILITE (I think)
33.275785,-96.670428
33.275785,-96.664037
– POINT (I think)
•
33.270593,-96.679770
33.274906,-96.679693
Features include
– LINE
•
33.265486,-96.679897
33.276579,-96.663242
StreetAtlas draw files are easy to manipulate,
but gps data may be out of order in the file
This causes straight lines to be drawn across
your map
33.278596,-96.663062
33.278403,-96.658340
33.278446,-96.656492
33.278446,-96.654438
33.278435,-96.652313
END
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
More to come…
I’m still working on this slide package. More file formats
are coming eventually!
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
UI-View Maps used during the
Dallas White Rock Marathon
A UI-View map created in
MapInfo. Used manually edited
GPS data, and a UI-View
overlay (.pos) file for display.
Each feature is loaded as a
separate data set and manually
tuned for the best appearance.
The .inf geographic reference
file was created by manually
mousing to the upper left and
lower right corners of the
window and converting the
coordinates with a calculator.
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
Links to Online Resources
•
Useful books from Navtech Seminars:
US Census Dept
– http://www.census.gov
•
US Geological Survey
“Glossary of Mapping, Charting and Geodetic Terms”
Defense Mapping Agency
– http://geography.usgs.gov
•
“Geodetic Glossary”
National Geodetic Survey
– http://www.ngs.noaa.gov
•
Navtech Seminars
“NOAA Professional Paper NOS 2, North American Datum of 1983”
– http://www.navtechgps.com
•
National Imagery and Mapping Agency
– http://www.nima.mil
•
National Geodetic Survey, Rockville, MD
National Geodetic Survey, Rockville, MD
“Map Projections – A Working Manual”
U. S. Geological Survey professional paper; 1395
Radio Mobile
– http://www.cplus.org/rmw/english1.html
•
UI-View Map tools
– http://www.uiview.com/uiview32/mapsoftware.shtml
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved
More presentations in this series available at:
http://www.n5oom.org/2004_hamcom/presentations.htm
APRS is a registered trademark Bob Bruninga, WB4APR
Copyright © 2003 – John Beadles, N5OOM
All Rights Reserved