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APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Maps for APRS John Beadles, N5OOM.

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Presentation on theme: "APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Maps for APRS John Beadles, N5OOM."— Presentation transcript:

1 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Maps for APRS John Beadles, N5OOM

2 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

3 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 MapsVector Maps –Raster MapsRaster Maps Map types used by various APRS Software Map Products useable for APRS Links to Online Resources

4 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

5 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

6 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: 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: degrees or degrees west.

7 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Lats & Lons on the Earth 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

8 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: , APRS uses degrees and decimal minutes –Example: N, W –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

9 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

10 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.htmlhttp://crunch.tec.army.mil/software/corpscon/corpscon.html Blue Marble Geographics –Industry standard tools, but expensive –http://www.bluemarblegeo.com/http://www.bluemarblegeo.com/ Gpsinformation.net –Has references to a lot of GPS data download tools –http://gpsinformation.net/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 for MS Windows portswww.perl.orgwww.activestate.com

11 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.

12 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Types of Maps Vector Maps Raster Maps

13 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 Lines and other objects are defined as coordinate pairs Maps with unformatted text can be pretty ugly Map features can be dynamically edited Sometimes used with associated database entries (Geographic Information Systems) Includes Tiger data, USGS DLG data used with some APRS software BEGIN LINE , , , , , , , , , , , , , END

14 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Is basically a picture Accompanied with a file containing associated geographic information 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 W, N W, N 2003 MS-150 Sun Lunch Stop Raster Maps

15 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Raster Map Example

16 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Map products useable for APRS

17 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Vector Data Census Dept TIGER Data –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 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

18 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Consumer Software Products Delorme StreetAtlas –APRS+SA –UI-View (some versions of SA) Precision Mapping –UI-View –WinAPRS Microsoft MapPoint –APRSPoint 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.

19 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

20 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.

21 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.

22 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

23 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

24 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

25 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.htmlhttp://www.softmaptech.com/en/pages/geotiff_EN.html Othertimes through government or public works sites Minimum contents of a sample.FGD file WEST BOUNDING COORDINATE: EAST BOUNDING COORDINATE: NORTH BOUNDING COORDINATE: SOUTH BOUNDING COORDINATE: Taken from:

26 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Xastir Pix Map Consists of two files –A pixel map (.xpm) –A geographic calibration file (.geo) Sample.geo file FILENAME world1.xpm # x y lon lat TIEPOINT TIEPOINT IMAGESIZE Sample.geo file FILENAME world1.xpm # x y lon lat TIEPOINT TIEPOINT IMAGESIZE geo files can have many elements: FILENAME filename This specifies the filename of a map image to be loaded from the local disk. URL 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. IMAGESIZE pixels horizontally pixels vertically 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. DATUM datum This feature is not implemented. 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:

27 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved UI-View Maps (from UI-Terra) Sample.inf file W, N W, N 2003 MS-150 Sun Lunch Stop 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. The name that shows up in UI-Views’ Maps list

28 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.

29 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Street Atlas Draw Files Draw files allow Street Atlas users a way to draw and save their own features in Street Atlas Each file consists of one or more files bounded by a “BEGIN” and “END” keyword. Each pair of coordinates represents a vertex in a line segment. Features include –LINE –HILITE (I think) –POINT (I think) 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 Sample StreetAtlas Draw File BEGIN LINE , , , , , , , END BEGIN LINE , , , , , , , , , END

30 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!

31 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.

32 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved Links to Online Resources US Census Dept –http://www.census.govhttp://www.census.gov US Geological Survey –http://geography.usgs.govhttp://geography.usgs.gov National Geodetic Survey –http://www.ngs.noaa.govhttp://www.ngs.noaa.gov Navtech Seminars –http://www.navtechgps.comhttp://www.navtechgps.com National Imagery and Mapping Agency –http://www.nima.milhttp://www.nima.mil Radio Mobile –http://www.cplus.org/rmw/english1.htmlhttp://www.cplus.org/rmw/english1.html UI-View Map tools –http://www.ui- view.com/uiview32/mapsoftware.shtmlhttp://www.ui- view.com/uiview32/mapsoftware.shtml Useful books from Navtech Seminars: “Glossary of Mapping, Charting and Geodetic Terms” Defense Mapping Agency “Geodetic Glossary” National Geodetic Survey, Rockville, MD “NOAA Professional Paper NOS 2, North American Datum of 1983” National Geodetic Survey, Rockville, MD “Map Projections – A Working Manual” U. S. Geological Survey professional paper; 1395

33 APRS is a registered trademark Bob Bruninga, WB4APR Copyright © 2003 – John Beadles, N5OOM All Rights Reserved More presentations in this series available at:


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