The Weather Forecasting Forum

There are two ways you can get images from satellites:
1 Receiving weather satellites
2 Download from internet
I will describe both ways. Using these procedures you get perfect fitting maps.

Fred

Receiving weather satellites

I use Wxtoimg (http://www.wxtoimg.com/ )for receiving APT-satellites. But I am sure that with the programs of David Taylor (see download from internet) it is also possible. Below an abstract of an article I wrote for the GEO Quarterly (see http://www.geo-web.org.uk).

Initial
Wxtoimg
Set in <Options/Projections options> the following parameters: latitude, longitude, north, south, west, east, scale. Choose values that will give the image you want. Remove the mark by “disable map overlay”, choose in <Projection> for “Orthographic” and generate the image. Write down the size in pixels (they will appear on the bottom of the screen, just before showing the image), choose <Image/White background> and save the image as BMP.

Digital Atmosphere
Generate a map. Use for latitude and longitude the same values as in Wxtoimg. Use for scale a size that generates more or less the same map as Wxtoimg. It is not so important at this moment. Give width en height the values from Wxtoimg. Generate the map and if it’s ok, save it with <Map/Save map> as BMP.

Fine-tuning
Repeat the next steps until both maps fits exactly.
1.Choose icon “load map” and read the Wxtoimg image.
2.Choose <map/add base map>. This option will project the DA-map over the image and will surely not fit. Now we must try to make the DA-map fit. This is done by making changes in <Map/Generate map/Enter lat/lon.> :
3.Latitude. This will move the map in vertical direction
4.Longitude. This will move the map in horizontal direction.
5.Scale for resizing the map.
6.Make small changes in the steps 3, 4 and 5. After <OK> DA will generate a new map.
7.Continue with step 1.
It can happen that meridians do not fit exactly onto each other. Then you can rotate the image in Wxtoimg by changing the “reference longitude”.

Finishing
Save the DA-map for the last time. This must be done because every lay-out has its own base map and parameter-files. Always open this corresponding map before loading a picture with a different layout from Wxtoimg.

The dimensions of the map can be changed by modifying the “width” in the parameter of Wxtoimg. Give width en height in DA the same values as in Wxtoimg.

Download from internet

In the RIG-journal 73 (june 2003) is an article by Thomas Scheelen ( http://www.rig.org.uk ). He uses some modules of David Taylor like HRPT-reader and Groundmap. My experiences are based on that article.

Setup
Download from http://www.satsignal.net/ the programs HRPT-reader and GroundMap and install them.

Download
Download files from http://www.saa.noaa.gov/. How to do this is described on http://www.satsignal.net/. On the page about HRPT-reader is a link to basic notes on using the SAA. The final results are one or more downloaded files.

HRPT-reader
Open a downloaded file. The main result is a false colour image. Save this image. On the background a location file is saved too.

GroundMap
Open the location file from the previous step. Choose “Ortographic” as projection and use a suitable output size. The image is showed. Save the image.
If Groundmap is not registered you have a few possibilities in output size. This means that you get a rather small image in DAWS. But you can see what is possible.


Initial
Digital Atmosphere
Generate a map. Use for latitude and longitude the same values as in the download. Use for scale a size that generates more or less the same map as GroundMap. It is not so important at this moment. Give width en height the values from the download. Generate the map and if it’s ok, save it with <Map/Save map> as BMP.

Fine-tuning
Repeat the next steps until both maps fits exactly.
1.Choose icon “load map” and read the GroundMap image.
2.Choose <map/add base map>. This option will project the DA-map over the image and will surely not fit. Now we must try to make the DA-map fit. This is done by making changes in <Map/Generate map/Enter lat/lon.> :
3.Latitude. This will move the map in vertical direction
4.Longitude. This will move the map in horizontal direction.
5.Scale for resizing the map.
6.Make small changes in the steps 3, 4 and 5. After <OK> DA will generate a new map.
7.Continue with step 1.

Finishing
Save the DA-map for the last time. This must be done because every lay-out has its own base map and parameter-files. Always open this corresponding map before loading a picture with a different layout from GroundMap.

This is good info. Let me know if I can add this to the documentation.

Thanks,

Tim

Of course

Fred

Can I get your last name? I do want to give you due credit.

Fred van den Bosch

Thanks!

Is there a way to automate this process for free??

It looks like that only way to get the Autoget program is if you pay for the program!

No!

The point is that the images you receive by a receiver or download from internet does not have the right projection. This must be orthographic. So you need a program like HRPT-reader/Groundmap or Autoget in combination with GeoSatSignal to make that conversion. See http://www.satsignal.net/

Greetings

Fred