There are a small number of map and image making tools that I offer on this page. The first is a tool which allows you to remap images as backgrounds for geostationary weather satellite data, the second is related to my WXtrack program, and allows you to make a customised master overlay, and the third is a set of programs for using some public data sources. I conclude with a note on data sources.
MapToGeo - for GeoSatSignal
MapToGeo allows you to take images in Plate-Carreé projection (azimuthal equidistant - linear latitude and longitude) and convert them into the view as seen by the current geostationary weather satellites around the world. This allows you to use the images as attractive backgrounds for GeoSatSignal, combining an idealised daylight image with the current cloud patterns, as an aid to weather presentation. This technique was suggested by Ferdinand Valk. The great thing is that images like the one below can be generated day or night - there is no need to have a daylight image for the region. This greatly extends the ability of GeoSatSignal to produce easily understood data right round the clock.
What the users say:
Here are some sample results from GeoSatSignal using a background (from Blue Marble) converted with MapToGeo. Many thanks to Ferdinand Valk for providing these sample images. He can be contacted for large format images like these with a superb print quality, and you can see Ferdinand's own comments about the program here.
You may find images of various sizes on the Web. There are limits to the size of images that MapToGeo can handle directly, but images up to 5400 pixels wide (east-west) and 2700 pixels high (north-south) should work in the program without problems. For generating the larger output formats, you will probably want to have at least 1 GB of memory in your PC.
To alleviate the image size problem, V1.0.2 of MapToGeo provides the option to use an input image which is only a fraction of the full Plate-Carreé projection, and combine the resulting output geostationary projection images in your favourite image editor (e.g. by arithmetic and taking the lighter image, or by using layers). There are three options for input image size:
The quoted sizes are not maxima, and you may be able to go a little larger, but perhaps not twice as large.
MakeOverlay - for WXtrack
This program will allow you to create a customised master bitmap image for using overlays with WXtrack and SatSignal. You can customise the grid-line spacing, whether a numerical annotation is displayed and its font, and whether or not the grid-lines should overlay countries. You should already have a working version of WXtrack, and the countries.dat file installed.Download MakeOverlay V1.4.0, 34436 bytes, revised 2002 Apr 04
If you do not already have the file countries.dat, you can download countries.zip here. You will need to unzip the countries.zip archive and extract the countries.dat file to appropriate location. Note that more recent versions of countries.dat include a few extra islands. If these appear to be missing from your version, check that you only have a recent copy, and not an old version in another folder. V1.4.0 allow the suppression of both grid lines and country boundaries.
Note that you will require a graphics driver that can handle more than the full resolution of the screen. This is usually true with Windows NT drivers, but may not be true with some Windows 9X graphics drivers.
LonLat2dat - updating Countries.dat
This small package contains a program to convert MapGen format (perhaps downloaded from the NGDC Coastlines Extractor) data into a format you can append to the Countries.dat file. Please note that this package is not supported by me, but self-help is available in the SatSignal Yahoo group. There are full instructions about updating Countries.dat in the Zip download.
Unsupported program which uses the signal strengths of GPS satellites (as reported by your GPS receiver) to determine your radio horizon. One side result is a polar plot of GPS satellite coverage, showing the hole in the coverage at the pole (as the satellites don't orbit that far north).
Other Mapping Tools
A few people have asked about the data and programs used to create the hill-shaded topographic map. Data came from GTOPO30 for topography, and GSHHS for shoreline and lake data, and I wrote my own programs to manipulate this data. You can download a 197 kB package containing pointers to the data, and the Delphi 5 source code that I used if you wish. This is really just for your interest, and is informal and not subject to any version control. Last updated, 2002 Mar 17. You will likely need a few other units if you want to recompile the programs, but they would be easy to modify to suit your own purposes. Please contact me if you have any notes or programs you might wish to add to this package.
Programs in the package
All these programs come with Borland's Delphi 5 source code ready for you to compile and use. You may need some of my other units from my Components page.
Blue Marble comprises a set of clear-sky earth images at various resolutions. Can be used with my MapToGeo program.
Observatory writes: "Everyone knows that NASA studies space; fewer
people know that NASA also studies Earth. Since the agency’s creation almost
50 years ago, NASA has been a world leader in space-based studies of our home
planet. Our mission has always been to explore, to discover, and to understand
the world in which we live from the unique vantage point of space, and to share
our newly gained perspectives with the public. That spirit of sharing remains
true today as NASA operates 18 of the most advanced Earth-observing satellites
ever built, helping scientists make some of the most detailed observations ever
made of our world.
The monthly global images may be found here - click on the image below to get a page of downloads!
U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Geophysical Data Center, 2006. 2-minute Gridded Global Relief Data (ETOPO2v2). This data is approximately 2km resolution at the equator, and has 1 metre height resolution.
The compressed raw data is about 72MB, and can be downloaded in both big-endian and little-endian versions.
has also kindly provided a Delphi program to create maps like that above from the
ETOPO2 data file. You can download an installation package here: http://leshamilton.co.uk/etopo2.htm.
Les is willing to make the Pascal/Delphi source code available, and if you are interested,
you can make your request to Les here: lesw (dot) hamilton (at) tiscali.co.uk.
Digital heights of the world and sea floor level. This is a single file of data at 5 minute intervals, making 360 x 12 points in longitude, and 180 x 12 points in latitude. Note that the file formats are slightly different, Jones having one extra 16-bit word per line of data (longitude), and being in PC order (little-endian, or low byte first).
Les Hamilton writes: "For VB5/6 programmers interested in learning how to make use of the ETOPO5 elevation data, I have developed this small Visual Basic program. You are free to download and modify it to suit your own map creation purposes. All source code is included".
There is a two-minute resolution version of this file which has Mercator projection covering most of the world at the URL below. It is about 136 MB uncompressed.
Digital heights of the world - at 30 second intervals. This data is divided into 33 tiles - about 50 MB each, but a lot less when compressed with Zip. You should be aware that the topography data occupies some 1.74 GB when expanded, but it is available at cost from the US source on CDs. Sources:
GSHHS is shoreline and lake data that comes at a variety of resolutions. You will probably find the low resolution data (5Km, 1.1MB) adequate, there are also intermediate resolution (1 km, 5 MB) and high resolution data (0.2 km) available. Its main use here is in adding lakes to the height data, which otherwise only has major seas.
If you need to resample to a different accuracy (I find about 2.2 km about right for HRPT data), there is a C program provided in the GSHHS archive which uses the Douglas-Peucker algorithm. Just in case you don't have a C compiler to hand, I have provided a ready-compiled version. Updated 2006 April 20 for the V1.3 GSHHS data - ready-compiled software V1.5 for V1.3 data.
I use the raw GSHHS data myself, although the authors offer a very fine map generation package called Generic Mapping Tools (GMT) which has a compiled version of the data.
Here you can get some land-sea mask data. Please see here for a full description: http://oceancolor.gsfc.nasa.gov/DOCS/ODPS_Land_Mask.pdf.