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  • #46
    yeah I am making some tests with a color replacer tool in Corel Paint Shop. Thanks

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    • #47
      Originally posted by JOLLY47ROGER View Post
      Yes, that can easily be done - but white is often not pure (255,255,255) - especially with scanned maps. I would suggest a threshold of R+G+B >=700, maybe configurable as a preference. Any alternative ideas? - as long as the rule is fairly simple I can put it in.
      Do you already handle alpha channels? (Haven't checked myself...)

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      • #48
        I don't handle alpha channels. Maps are only handled internally as 24-bit RGB images.

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        • #49
          Originally posted by JOLLY47ROGER View Post
          I don't handle alpha channels. Maps are only handled internally as 24-bit RGB images.
          Ah. Alpha handling might prove to be more flexible than arbitrarily marking a color as transparent.

          With some maps, the trick I use to generate "transparent trails" is to load the image in GIMP, and:
          1) Add layer mask as a greyscale version of the image in Layers, Channels and Paths. (Checking the "invert mask" box)
          2) Select the layer mask and use the Levels tool to turn anything darker than a value to "transparent" and lighter than a certain value to "opaque". (Note: Dark in the layer mask = light in the original) - With the Levels tool you can have a narrow "band" of value ranges that aren't mapped to the extremes of the output, which preserves antialiasing somewhat (as opposed to the threshold tool which does not)

          Save this as a PNG with transparency. This can be overlaid onto satellite maps using gdalwarp, if georeferenced. (MAPC2MAPC is pretty good for performing the georeferencing.)

          I'll try to post an example soon. Unfortunately many of my examples prove to be not quite to scale and don't align as well as I would like.

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          • #50
            Hi i have been trying to improve the quailty of the maps i produced in the example above and think i am there.

            Here is an example at 300ft zoom you can see that there is now know blockness round the writing and it is much clearer



            Here is the same map at 80ft zoom you can see the os maps have lost there clarity but the sat map is still nice and clear.



            If anyone is intresed and can put together a HOW TO

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            • #51
              Would be most interested in that please.

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              • #52
                Dear Garmin users,

                I have used Garmin Oregon 450 model two days and was able to create custom maps using Google Earth.

                Did I understood right that the only map format that Garmin supports is KMZ? You can't use any other formats like shp, ecw, geotiff or so?

                In some softwares, like Geosoft, you can export the map you have done directly to KMZ- format. If you put this KMZ-file direct to Oregon, it won't work. I have extracted this file and noticed that file doc.kml is different than the one that is created using Google Earth. I also noticed that in Google Earth there is propably two ways how to put coordinates to your JPEG-picture. The only difference is that the other way works and other don't work in Oregon. So it looks like Oregon is very strict to KML-file format, even Google Earth can understand different kind of KML-file formats? Do you agree? I noticed that there is software called mapc2mapc that could fix these problems. I haven't installed it yet. Do you find it useful?

                Thanks, S

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                • #53
                  Originally posted by SANIEMI View Post
                  Dear Garmin users,

                  I have used Garmin Oregon 450 model two days and was able to create custom maps using Google Earth.

                  Did I understood right that the only map format that Garmin supports is KMZ? You can't use any other formats like shp, ecw, geotiff or so?

                  In some softwares, like Geosoft, you can export the map you have done directly to KMZ- format. If you put this KMZ-file direct to Oregon, it won't work. I have extracted this file and noticed that file doc.kml is different than the one that is created using Google Earth. I also noticed that in Google Earth there is propably two ways how to put coordinates to your JPEG-picture. The only difference is that the other way works and other don't work in Oregon. So it looks like Oregon is very strict to KML-file format, even Google Earth can understand different kind of KML-file formats? Do you agree? I noticed that there is software called mapc2mapc that could fix these problems. I haven't installed it yet. Do you find it useful?

                  Thanks, S
                  Yes, the Garmin Custom Maps KMZ is a subset of the full Google Earth GroundOverlay KMZ structure. There are limits on file type (JPEG, cannot be progressive) and file size (each tile must be <1 Mpixel or the unit will scale it down), along with number of tiles (100 across all maps) - these limitations are pretty well documented. There are some filename restrictions that are less well documented.

                  If you want to load GeoTiff, etc in various projections, you will need to perform a conversion. MAPC2MAPC is great for some formats, but doesn't support everything. I personally use a workflow based on:

                  gdalwarp from the GDAL package to reproject stuff to an EPSG:4326 projection and save it to a GeoTIFF file

                  listgeo from the GeoTiff utilities package to generate a TFW from that GeoTiff

                  MAPC2MAPC to take that GeoTiff and generate a tiled Garmin Custom Maps KMZ following all of the known GCM restrictions.

                  I also use MAPC2MAPC as a user interface for generating ground control points that permit me to calibrate non-georeferenced maps. MAPC2MAPC's author just added a feature (CSV export) that makes it very easy to take ground control points chosen in MAPC2MAPC and use them as input to gdal_translate's -gcp option, which is a great timesaver when you have 20-30 GCPs for a map. (You need LOTS of GCPs if you are attempting to georeference and warp an image that is not geometrically correct using gdalwarp's Thin Plate Spline warping algorithm.)

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                  • #54
                    Originally posted by SANIEMI View Post
                    Dear Garmin users,

                    I have used Garmin Oregon 450 model two days and was able to create custom maps using Google Earth.

                    Did I understood right that the only map format that Garmin supports is KMZ? You can't use any other formats like shp, ecw, geotiff or so?

                    In some softwares, like Geosoft, you can export the map you have done directly to KMZ- format. If you put this KMZ-file direct to Oregon, it won't work. I have extracted this file and noticed that file doc.kml is different than the one that is created using Google Earth. I also noticed that in Google Earth there is propably two ways how to put coordinates to your JPEG-picture. The only difference is that the other way works and other don't work in Oregon. So it looks like Oregon is very strict to KML-file format, even Google Earth can understand different kind of KML-file formats? Do you agree? I noticed that there is software called mapc2mapc that could fix these problems. I haven't installed it yet. Do you find it useful?

                    Thanks, S

                    I've had similar problem with kmz-files exported by http://g4ng.com (which I'm working for, sorry for this little advertising :-). After a lot of experiments I figured out that Oregon can handle complex kml markup and directory structure properly and without problems.

                    But what is important and is never mentioned in requirements for custom maps is that a doc.kml file must be the first file in the kmz's zip-archive.

                    There is a post in this thread on page 2 from Ferengee addressing this issue. However his solution can't help it you have a kmz-file already created programmatically unless you want to re-zip it manually.

                    Maybe it's worth to mention this requirement in this thread's first message or other places where requirements for custom maps are provided, as this is quite mysterious and hard to debug issue.

                    The device I've used is Oregon 300 with software version 3.80.

                    Hope this helps.

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                    • #55
                      zoom levels and visibility

                      Has anything changed regarding the resizing of images with custom maps? I've been experimenting loading custom maps to a GPSmap62 st and it seems that depending on the resolution of the .jpeg used the custom map is visible from different zoom levels.

                      For example, I started with a 5500x5000 pixel image and it was visible only from a zoom level of .8 miles down to 80 ft, then when I used a .jpeg that was 1024x900 pixels it was visible from 5 miles to 500 ft and anytime I zoom in or out past those levels the custom map dissapears.

                      It also seems to be affected by resizing the image in google earth as well. When using the 5500x5000 pixel image and actually shrinking it to the correct size then sending it to the gps I was unable to view the custom map at any zoom level at all.

                      Any ideas?

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                      • #56
                        I think it has to do with the resolution of the map and not the pixel dimensions. In other words, if the source image is 10 feet per pixel, it will be visible at lower zoom levels (.8 miles, perhaps) whereas a 1 foot per pixel image will only be visible at higher levels (.2 miles, maybe).

                        So it depends on your source imagery. 10 feet per pixel is a good sample size for scanned USGS 24k topo maps, Google imagery might be 1 meter per pixel while some of the better aerial imagery is 1 foot per pixel.

                        I use Globalmapper which is a powerful GIS program that makes it easy to resample the source imagery at any resolution. Not sure if any of the current shareware/freeware programs also have this capability.

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                        • #57
                          MAPC2MAPC allows re-scaling of maps. When the map is loaded it calculates metres per pixel and rescaling is done as a percentage - so 50% doubles the metres per pixel.

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                          • #58
                            [*] I am not agree with above. The maximun tiles in .kmz files mut be less than 10. For this reason I can create one big image with 1m of resolution, size 4096x4096 in .map format, recover the image and export with global mapper (for example) and choose Export Web format (KML, KMZ format) with .jpg format, display when file is 256 pixels in size, with grid cell size 2048 and creating a compressed KMZ files with 5 cells. The custom map image created is bigger than 3MB (more than 2x3MB=6MB). Since my point of view, the real problem are the blanks areas created in tiles due to the .jpg format instead of transparents .png images.
                            Last edited by notengoquemostrarnada; 02-12-2012, 06:38 AM.

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                            • #59
                              Originally posted by RBARRIO View Post
                              I am not agree with above. The maximun tiles in .kmz files mut be less than 10.
                              What don't you agree with? I have made many custom maps with ~100 tiles in the .kmz file and they work fine.

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                              • #60
                                Micro SD cards

                                What size microSD card should I get for an Oregon 450? It seems that at a maximum 100sq miles of jpg images there is no need for a gigantic, and expensive, microSD. What might be a reasonable, useful upper size limit for the card? I intend to max out the card with detailed 1:50k topo maps. If I can only load 100 jpgs and each jpg must be less than 3MB and I cannot load more than one set of contiguous tiled jpgs at one time (as a single kmz file because the unit cannot address more than one) then the maximum size is 300MB and anything bigger is a waste, true?
                                Last edited by JEREMYPWATSON@GMAIL.COM; 02-16-2012, 01:59 AM. Reason: Thought about it a bit more

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