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Thread: Aligning map with over 100 counties (overlay)

  1. #1
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    Default Aligning map with over 100 counties (overlay)

    This may be a really easy fix (esp for those with versions other than the free one), but searching through the internet and these forums still haven't helped me solve this problem

    Problem - I have a 2D map colorcoded for over 100 counties (png file) that I can't align when adding an overlay

    I created it by:

    1) putting a black overlay over all of the area (to create a contrast between the county lines [when zoomed in] and the terrain)

    2) taking multiple screenshots of the area (roughly 20) using SnagIt when zoomed in enough to have the county lines appear

    3) using photomerge in photoshop to piece all of the pictures together into one much larger file

    4) color coding via fill with photoshop

    5) touching up the photo

    6) saving as a png (preserving the transparency)

    ===================

    Since I have the free version it doesn't automatically place the image for me, and for the life of me I can't get it to line up. The instructions in the sticky thread don't make sense to me. The actions that be done using screenshots "1" & "3" (akin to using a drawsting according to the instructions - which I interpreted to mean the 2D image being 'adjusted' to work with the curvatures made by google earth to make the earth 3D) utilize a feature I can't find. All I can do is adjust the height/width and rotate the picture (and I've zoomed in a lot, I wonder if it had something to do with the upgrades to google earth since the post was written). Also, since it is such a large area (some 1000KM wide), trying to manually adjust it requires a zoomout, which gets rid of the county lines from Google Earth, making doing it manually virtually impossible.

    Someone made a comment about putting pieces of paper of various sizes on a basketball, saying it won't look good regardless (his point was to disprove that bigger is better), but I have to think there has to be some way for it to work somewhat easily.

    If it's easiest to have someone with an upgraded version just have google earth automatically place it, I would really appreciate the good Samaritan.

    Thanks in advance for the assistance.

  2. #2

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    It has nothing to do with Free vs. Pro version of Google Earth. The person that mentioned the basketball is exactly correct. Try taking a flat piece of paper and wrapping around something round, like an orange. Notice that it doesn't wrap very nicely....that's the same thing you're seeing.

    What you're trying to do requires GIS software and a basic knowledge of GIS.

    Matt
    Matt Fox

  3. #3
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    Not sure that the round ball/flat paper theory comes into play on something that's only 1,000 KM (621 miles) wide.

    Matt is correct, none of the GEarth versions will automatically place the overlay.

    BUT -

    You say you took twenty screenshots using SnagIt. Can you find where the four corners of the overlay belong? If you could put a temporary placemark (when zoomed in way close) for each corner, then you could zoom in and out making course and fine adjustements until all four corners are lined up to within a few inches of where they belong.

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    Thanks for the reply guys.

    The problem I am seeing is that I can get it to line up pretty good in one county, but as i drag and rotate, it always gets out of alignment as I get farther away from where I am adjusting (which seems intuitive, I know, just making observations).

    I attempted to place 4 placemarks when zoomed in to try and adjust it zoomed out so it would line up, and it was able to line up in that county, but as I mentioned before, it would get out of alignment as I moved farther from that corner.

    In regards to knowing the coordinates... The way photomerge works I needed to have the screenshots overlap and photoshop pieced together the "puzzle". When I did the necessary editing to the image in photoshop to get it prepared for import, I removed the unnecessary counties to make a unique shape (taking away from the "rectangle" to make a shape of 100 something counties with a transparent background as the rest). Long story short, I have no idea what the coordinates are, and the 4 corners of my overlay are transparent.

    Perhaps someone could give me a different suggestion (other than screenshots and photomerge) for getting a 600 mile wide and roughly 300 mile tall image with the county details that would allow me to know the coordinates. I chose that option after asking questions regarding getting a large (somewhat) hi-res image of a large area and was recommended that route.

    There are examples on here of states where the counties are color coded, but no PMs I have sent back have been replied to and I couldn't find a tutorial anywhere online for the life of me. If someone could explain that to me, I would be able to follow that and avoid the mess I'm in now.

    I have a theory as to why my problem exists, perhaps someone can share some insight. To refer back to the basketball example, when I take the screenshots it is of multiple closeups of the basketball, so the 3d curvature is less pronounced, but when I do the overlay it is zoomed out (b/c I stitched together 20 images, in essence) and the curvature is more obvious. Is this plausible, or does the "aggregate curvature" over the screenshots equate to the curvature the zoomed out image would possess???

    Sorry for the long post. Thanks again,

    Dan

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    I don't think the curvature of the earth will be an issue for a 300 x 600 mile overlay. But I've been wrong before.

    This should work:


    • Take your 20 screenshots. (Make sure north is always up, I noticed you mentioned rotating the overlay - no need to add more variables.)
    • Use Photomerge to put them together.
    • In Photoshop, make sure you have everything as one non-background layer. Name this layer "Tom".
    • Use your marquee tool and duplicate a 5x5 pixel block from each of the four corners.
    • Make all four of these blocks into one layer and name this layer "Dan".
    • Go back to layer Tom and do all the filling and removing of unnecessary counties.
    • Merge layers Tom and Dan so that you end up with one layer.
    • Save as .png and now you should be able to adjust the overlay by zooming into each of the four corners (in theory you only need two opposing corners) and adjusting.

    Let me know if this works.

  6. #6

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    Or, you could save yourself a lot of trouble and spend $30 on Shape2Earth. It's a plugin for free GIS program called MapWindow. It will import a county boundary Shapefile (which you can find free online). Then you can assign colors to counties, and export as KML polygons.

    http://shape2earth.com/default.aspx

    Matt
    Matt Fox

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    Updates

    I made a black image overlay and recorded the 4 coordinates. I then took the screenshots and after merging them, tried to import just the black box I made (which should have been identical to the overlay I already had). It didn't work, so I thought I would try some GIS

    ======

    I then downloaded MapWindow and Shape2Earth to try and get this to work. I downloaded county shapefiles from VDS technologies and the US Census Bureau. I am having difficulties picking the specific counties I need (attempting to edit it through mapwindow) and finding a way to color code them. It doesn't appear to be as easy as recommended.

    Any recommendations?

  8. #8

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    Try this.

    1) Open your shapefile in MapWindow
    2) Use the Select tool to select the counties you want to use
    3) Go to GIS Tools Menu and select "Export Selected Shapes to new Shapefile".
    4) Close the original shapefile and open the new one you just created that only has the counties you want.
    5) Double click on the county layer under the Data Layers list on the left side of screen
    6) Click on Coloring Scheme to color the county polygons.
    7) Export as KML

    I think that will do what you're trying to do.

    Matt
    Matt Fox

  9. #9
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    Matt,

    You are a genius!!!! Thank you so much for the help.

    (I added a field and put in values for it and color coded based on unique values for that field, I needed 3 different colors, which worked like a charm)


    Thanks again everyone!

  10. #10

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    Glad to hear it worked. You can do a lot of cool things with shapefiles, MapWindow and Shape2Earth plugin.
    Matt Fox

  11. #11
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    Dan - you've got to post your file here or in the file library, we want to see what you've worked so hard on.

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