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TOPIC: Satelite image on HDS screen

Satelite image on HDS screen 7 years 10 months ago #1478

  • gpiverson
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Keyhole Mode, generally, is completely skippable because it's functionality was built directly into the Raster Mode.

Raster Mode and Keyhole Mode automatically calculate the world file (.pgw for .png) when they find an appropriately formatted KML file. This mode will not try to replace a world file if one already exists.

However, if the KML is run directly through Raster Mode, it relies on the .png being located in a sub directory of where that KML file is (or later in the folder parsing). This is the normal internal folder structure of the KMZ zip file.

The logic of the Raster Mode process during the file collection stage goes:
- Recursively parse the folder structures provided to the application
- If it finds a KML file, parse the XML and generate any non existing world files on images
- If it finds an image with an associated world file, store the file name, resolution, and extents in a cache for later use.

This allows the raster mode to load very large raster datasets at the expense of reading all the images once to populate the cache and knowing which specific files it needs from there on.

So, in short, do what Matt mentioned but you don't need to run the Keyhole Mode except for specially formatted KML files.
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Satelite image on HDS screen 7 years 10 months ago #1479

  • gpiverson
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This may also help you understand what world files are and why they are used: en.wikipedia.org/wiki/World_file
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Satelite image on HDS screen 7 years 10 months ago #1480

  • Talon
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Wow! All of the support and information in such a timely fashion is unbelievable. Thanks so much!

Danny emailed me a set of AT5 files he created and the aerial images appeared perfectly on my HDS. Very nice.

Matt's explanation is great, as is the information provided by gpiverson. My problem has always been with the .kml and .kmz files. I can create a file with a .kml suffix or a .kmz suffix (zipped .kml), and I understand there should be two parts to the file (image and spatial reference) but I have no idea how to extract the various components from these files. Or even if the files were created correctly to begin with. I know when I reopen the files in Google Earth, they return me to the correct image and location.

The .kml file I am working with was created by SAS Planet, so I have no clue what it contains and I can't seem to find a program which will extract the components. I read about the IMC raster process using a "world file" and saw how the Keyhole Mode was supposed to create the components, but I never see the creation of .pgw files or even a separate image file for that matter.

I have studied the IMC help file example showing how to extract the various components of .kml and .kmz files and how the program created a folder for use in the IMC Raster mode. I even bought and installed WinRar to follow the example, but it will not extract any files to a folder. I understand the Raster Mode of IMC wants a folder which contains an image file and a reference file. How do you ever break a .kml or .kmz file into those components? If I could ever get a folder for Raster mode input I think the rest would be down hill.

Thanks again for all of the support!
Last Edit: 7 years 10 months ago by Talon.
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Satelite image on HDS screen 7 years 10 months ago #1481

  • gpiverson
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It's difficult to be too much more specific.

My personal preference for zip programs is 7Zip (which is freeware). WinZip and WinRAR should be able to handle these files but 7Zip definitely can. The KMZ file uses a simple DEFLATE method for compression.

When you unzip the file, it should unzip to 2 files:

<RootFolder>
-"doc.kml"
-"files"
--<image file name>

The doc.kml, if you open it up in a text editor like notepad will show an XML structure like this one...a <GroundOverlay> containing an <Icon> reference (the image with a local - not absolute - reference) and a <LatLonBox> reference (the extents)

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="www.opengis.net/kml/2.2" xmlns:gx="www.google.com/kml/ext/2.2" xmlns:kml="www.opengis.net/kml/2.2" xmlns:atom="www.w3.org/2005/Atom">
<GroundOverlay>
<name>Untitled Image Overlay</name>
<color>96ffffff</color>
<Icon>
<href>files/chart-nz-5_1-0005-0003.jpg</href>
<viewBoundScale>0.75</viewBoundScale>
</Icon>
<LatLonBox>
<north>-36.38468155987549</north>
<south>-36.62718367028314</south>
<east>175.7278146808112</east>
<west>175.4837582938124</west>
</LatLonBox>
</GroundOverlay>
</kml>

In my case, I ran through a file "Waikawau.kmz" some kiwis sent me.

It broken down to:

"D:\"
-"Waikawau"
--"doc.kml"
--"files"
---"chart-nz-5_1-0005-0003.jpg"

after (optionally) running the keyhole mode, it expanded to:

"D:\"
-"Waikawau"
--"doc.kml"
--"files"
---"chart-nz-5_1-0005-0003.jpg"
---"chart-nz-5_1-0005-0003.jgw"

I can then add the "D:\Waikawau\" folder to my raster mode and it will run through.
Last Edit: 7 years 10 months ago by gpiverson.
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Satelite image on HDS screen 7 years 10 months ago #1482

  • Talon
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In summary it appears I don't know how to create adequate .kml or .kmz files. I was finally able to get WinRar to extract files from a .kmz I created from a polygon path in Google Earth, but the extraction only returned the doc.kml file...no image files. The .kml from SAS Planet will not even open in WinRar. The error message says "No Archives" found.

How do you create the correct type of input file to begin with?
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Satelite image on HDS screen 7 years 10 months ago #1483

  • gpiverson
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It's probably easiest to reference a video showing Garmin's method of creating KMZ files



This will show step by step in a youtube video how to create a KMZ file with an image. Polygon Paths are not preserved from the KML file (only image references).
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Satelite image on HDS screen 7 years 10 months ago #1484

  • gpiverson
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Also, try 7Zip instead of WinRAR. The SAS files should already be formatted correctly for you. This video details geo referencing an image and storing it in a KMZ file.
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Satelite image on HDS screen 7 years 10 months ago #1485

  • Talon
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Gpiverson...thanks for the detailed explanation. Makes perfect sense and as my last post indicates I have been struggling with inadequate input files (.kml and .kmz) all along. Now I need to figure out how to assemble the correct starting files.
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Satelite image on HDS screen 7 years 10 months ago #1486

  • Talon
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I downloaded and installed 7Zip, but it too could not open the .kml files I created from SAS Planet. The files are 10-12 Mb so they probably contain image and reference data, but I can't get it extracted.

All the program help files and online support I have found are written in Russian.
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Satelite image on HDS screen 7 years 10 months ago #1487

  • gpiverson
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You're welcome.

I work for Lowrance and I wrote the IMC so I know a bit about how it runs. Matt is pretty much the resident expert on Reefmaster. A lot of other people on this forum have significant GIS experience. My (and probably Matt's) specializations are not customer service so it's always helpful to have other people on these forums answering questions.

The IMC was designed with support by user community in mind so answering questions on forums helps seed knowledge to the user community so they, in turn, can help other people. This is probably the best English forum around for asking questions on how to process maps with either application.
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Satelite image on HDS screen 7 years 10 months ago #1488

  • Talon
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Greg,

Once again, thanks for all of your help. I am a Lowrance Pro-Staff member and on the External Validation Team. I am in contact with folks out your way quite often...almost daily of recent with all of the projects going on.

I really like the AT5 format for the locator mapping and I am trying my best to learn and better understand the vast capabilities in order to help others. I just wish my GIS skills were better, but I will keep pecking away at it.
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Satelite image on HDS screen 7 years 10 months ago #1490

  • gpiverson
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Ran back through this and I'm understanding how that export works now...looks like I found a bug I need to fix, as well...

The KML files are not zip files but are processed KML files with the associated links. The files are not downloaded to a sub folder but are always downloaded to the cache\sat\zX folder instead. If the exported file points to a reference that can't be stored in a relative path, the link is messing up.

(From Status Window Page)
20:04:00> Processing KML files for Image Coordinates
20:04:00> WARNING: Image File "D:/SAS_Export\C:\SAS.Planet.Release.131111\cache\sat\z14\2\x2077\2\y2976.jpg" could not be read. Skipping this file.
...
20:04:00> Process Complete!

Make sure to export the file with "Relative Path to Tiles" Selected and then your process folder for Raster Mode is going to need to be the files pulled from the cache directory. You'll need to run the Keyhole Mode unless you export to the cache\sat\zX folder and if you do that, you'll just need to run the cache\sat\zX folder in the Raster Mode.

The cache creates multiple folders in the cache\sat\ folder (z1 through z28 with 1 being the most zoomed out layer and 28 being the most zoomed in layer). Each of these layers will need to be matched to corresponding IMC Raster Zoom Levels but it will be easier just starting with a single zoom layer.

So, step by step:
Delete all files in your cache\sat\zX\ folder or, to be surgical, everything that has an extension that ends with a *.*w or *.kml - we only need to delete the world files and kml files.
Open the SAS program
Create a google kml export in the cache\sat\zX\ folder with "Relative Path to Tiles" selected (the application will need to recache the images but this will make sure you don't grab extra images that the IMC will pick up and use)
Run the IMC Raster Mode with the cache\sat\zX\ folder as a source folder
Grab the At5 files created and throw them on a card.

Note that instead of deleting these, you'll also be able to copy this out to another location because you used relative pathing on the KML image references.
Last Edit: 7 years 10 months ago by gpiverson.
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