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  • #31
    Originally posted by MUSK_OX View Post
    You just touched very important thing. Most people want high level of detail and bigger area of coverage. But sometimes raster data could be resampled to lower resolution without actual loss of details (there are lots of slightly blurred photos). I'm trying to find a good simple solution to get minimal size of detail from image, compare it with pixel size and resample image to remove any redundancy. There are some image analysis solutions with GUI, where maximum frequency in periods/pixel could be found for any image, but I want to find some console application with text output.
    big question need help
    i use 1 foot color orthophotography.. downloaded from utahs gis portal, they come in a 16000 x 16000 geotiff @ 72 ppi ... about 42 Mb ...in photoshop i use a plugin called avenza.geographicimager ...that saves the geo info so i can resize .. edit , and so on ... i change it to 155 ppi " is this the correct ppi?" then i resize to 5000x5000 ... so i can use four images , a total of 10000x10000 .. that can be sliced to a 100 tiles under 1024x1024 ...
    now starting at 1 pixel equal's 1 square foot .. in a mountain image one pixel could be a different color then the next ( a rock next to a bush) causing color noise ... in photoshop i use a median filter that will take to joining pixels that are close in color and makes them the same helping in color noise when zoomed in past 80 ft.. then i do some shadow fixing, sharpening and other photoshop tricks .... but garmin units see a much smaller color gammut then my images ... so now i'm seeing some odd colors... not terrible but noticable ... back before the google earth update when you had to use programs like Cgpsmapper .. and bmap2mp .. there was a garmin color index going around, that in photoshop you could convert your image colors to that, that garmin handhelds use .. i have lost mine ... and now can't find it anywhere online.. is there anyone out there THAT CAN PLEASE HELP... and don't get me wrong i'm getting great looking maps just want to tweek a few things to make them better
    Last edited by wadehinkle73; 01-31-2010, 04:51 PM.

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    • #32
      to follow up i my last post if you look at ostroffo1's examples on page 2 , on the top of his 50 ft example you can see,, if you had to make your way threw that thick brush in the dark you'd have a hard time ... but if you look close you can see the odd color noise in between the bushes ...(blurry, purplish hue). not terrible in his example but in a utah rocky mountain much more noticable ... the miedian filter i mentioned earlier ... really helps in makeing a more consistant color in the area's between the bushes ,.. but if you have two close colors next to each other one out of are handhelds gammut then it picks a close color on it's own ... causing color noice ... and odd color hues ...
      .. am i just asking to much or being to anal .... lol i just think if i could get back ahold of that garmin color index .. i could make some noticable inprovements to my maps


      ps: garmin uses a 256 color index , at least to my understanding ....and i have tried simply reducing my colors in the image , but ended up with bad results
      Last edited by wadehinkle73; 02-03-2010, 10:46 AM.

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      • #33
        Is it possible to have several layers of custom map.

        I would like to have sat images and UK O/S maps in the same KMZ.

        The OS maps would be on one zoom level and the sat images on another level.

        Wondering if Draworder is the solution

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        • #34
          No, not possible. Draw order does determine the order maps get drawn on the device. But once that order is set, it is fixed, and whatever map is on top, stays on top, regardless of zoom level.
          Last edited by FRITZ_NEWTON; 05-10-2010, 01:26 AM. Reason: correction

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          • #35
            Originally posted by WHITEDRAG0N View Post
            Is it possible to have several layers of custom map.

            I would like to have sat images and UK O/S maps in the same KMZ.

            The OS maps would be on one zoom level and the sat images on another level.

            Wondering if Draworder is the solution
            Not in this manner. It IS possible if you have one set that has transparency to overlay it prior to generating the KMZ.

            I do this with trail maps containing transparency and sat imagery - I georeference the trailmap using MAPC2MAPC and generate a world file.

            I then generate a combined satellite map image, reprojected to EPSG:4326 using gdalwarp

            I overlay the georeferenced trailmap + worldfile onto the sat imagery using gdalwarp

            Then I take the output from gdalwarp, use 'listgeo' (Google it) to pull out a worldfile, which I then load into MAPC2MAPC to generate a KMZ.

            I'm going to type up a more detailed HOWTO on this eventually.

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            • #36
              a how too would be great i have the area I want in 2 KMZ file so i too want to set my OS map level as transparent and my lower level as SAT.

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              • #37
                Have you tried using the MAPC2MAPC merge maps to create what you want? : Use the satellite as the 'base map' and the OS map as the 'merge map' and try different transparency levels (50% first). See this tutorial : http://www.the-thorns.org.uk/mapping/MAPMERGE.pdf Don't worry about different scales or projections....

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                • #38
                  Here's a sample of what can be achieved.
                  Last edited by johnthorn; 07-08-2010, 09:29 AM.

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                  • #39
                    Is there a way to define a "transparent" color in the merge map, so that this color, for example: white is not used when drawing the merge map over the base map?
                    Last edited by JBADILLA; 05-11-2010, 05:08 PM.

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                    • #40
                      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.

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                      • #41
                        Ohhhh just took a look at the example map you posted thats exactly what i was trying to achive.

                        Will have a go tonight. Will post results online later

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                        • #42
                          I've put the option to treat as transparent in version 2.4.7 setting a default threshold for R+G+B of 700 (which can be altered)

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                          • #43
                            Had a qucik play with the Hybrid Sat /OS maps and here is what i have come up with.





                            Any comments welcome

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                            • #44
                              Nice Examples, I made a test merging some 50k raster topo maps over google hybrid imagery downloaded with Mobile Atlas creator. The only detail is in some parts I have seen I might be wanting to remove not just a white background from the merge operation but some other color (such as green used to mark forest coverage). The result might not be as nice as having vector contour lines over the aerial imagery, but its nice having an option in places like my country where there is no commercial options avalable as vector topo maps for garmin units


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                              • #45
                                You could use a tool like Photoshop to change specific colours to white before the merge.

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