© 2012+2013 - Stefan Lewandowski

Quadtree Browser and Overlay Generator

	Center - Lat / Lng: / Tile X: Y: Zoom: Quad: Tile Bound S: W: N: E: Add/Remove Tiles: Quads: Bounding Box S: W: N: E:
for zoom level resulting number of tiles: View some sample tile URLs, replace x coordinate with [[XX]], y with [[YY]], zoom with [[ZZ]], quad with [[QQ]]. If you additionally replace different servers with [[SabcdS]] or [[S01234S]] resp., download may get faster (to be tested). You can save the URLs to fileWithURLs.txt and use a download tool, e.g. command line tool wget: wget -i fileWithURLs.txt (add option --no-check-certificate on https servers, add option -x -nH if the coordinates are spread over directories).
from to Create directories (must include [[QQ]], other "[[..]]" remain unchanged) for zoom level You can save these commands to a batch file (somename.cmd in the directory where you saved the tiles) and execute it.
Many target devices have a limit on the number of tiles, so we'll assemble multiple tiles into one at a time Assemble each 1x1 / 2x2 / 4x4 / 8x8 / 16x16 / 32x32 tiles (it's necessary to generate 4x4 tiles first, remove these afterwards) to a tile of 256x256 / 512x512 / 1024x1024 / 2048x2048 / 4096x4096 / 8192x8192 pixels Complete path where to find montage.exe (from ImageMagick software suite) Quality setting in montage.exe Create directories (only [[QQ]] is replaced, other "[[..]]" remain unchanged) for zoom level Die Begrenzung bei den Zoomlevels muss noch die assemblegröße berücksichtigen = in Funktion auslaugern und die jeweils aufrufen
Generate .kml with tiles of Zoom level taken above and using [[QQ]].png as file name (in subdirectory tiles). Tiles of higher zoom level will keep their zoom level. Tiles of lower zoom level will be replaced with tiles of the chosen zoom level.
Hints: Correcting erroneous parts - sometimes maps display distorted data that is correct on higher zoom levels - download the tiles at higher zoom levels (for those parts), assemble and resize as appropriate Tokens in tile URLs - some map services use varying tokens for different tiles; try using a constant token value or skip the token=... part Fehlende Kacheln automatisch runterladen und umbennen, jeweils in benötigter Zoomstufe heißt: auf Basis der "18" und der "4x4" die Quads bzgl. Zoom 16 durchgehen, also schauen, welche Zoom 18 fehlen: Könnte man das update benutzen: aus den Sub-16ern eine Liste der 16er-Zooms erstellen und die Sub-16er-Zooms per Delete rausziehen (die als 18er runterladen) Analog dann für die Zoom3less: Liste der 13er aus Sub-13er-Zooms erstellen und die Sub-13er sowie die auf 16er aufgefüllten Quads rausziehen (die als 16er runterladen) Ggf nochmal ne Ebene drüber weitere 3less: Also 10er aus Sub-10ern, Sub-10er und auf 13 aufgefüllte raus und als 13er runterladen. EigeneNamen für die Zusatzkacheln 1024er/8192er-Kacheln in angelegter Verzeichnisstruktur ablegen / hier neu anlegen (wäre mit KMZ[[QQ]] vs. SRC[[QQ]] auch nicht dumm) bei mehreren Stufen: Resize und reuse oder download from scratch
Trivia: most map services like Google Maps use Mercator projection. With its characteristic to preserve angles scale is equal in all directions around any point, thus shapes of small objects do not appear distorted, but scale increases from the equator to the poles. At lowest zoom, the world - cut to a square - fits into one tile (all tiles are 256x256 pixels). The Mercator projection is infinite in north-south direction; cutting the world to a square means cutting off everything north/south to a latitude of about +/- 85.0511 degrees. At zoom level 18 one pixel corresponds to 0.0000054 degrees longitude and between 0.0000054 and 0.0000005 degrees latitude at the equator and at 85.0511 degrees latitude, respectively; at maximum zoom level 20 these values are smaller by a factor 4. So 6 fractional digits are enough to represent longitude and 7 fractional digits to represent latitude. Talking in terms of scale one pixel in zoom level 18 corresponds to about 0.6 metres at the equator, about 0.3 metres at 60 degrees latitude, and about 0.05 metres at 85.0511 degrees latitude; again, at zoom level 20 these values are smaller by a factor 4; note that there are hardly any tiles beyond zoom level 16 at high latitudes (> 70 degrees).
Manual / How-to: Browsing the map and choosing tiles: - use the map as in Google maps (it is a Google map application - only StreetView is disabled and zoom control is set to be small) - the tile (at current zoom) containing the center is highlighted in red (you always move the map, not the red tile)   - the according coordinates are displayed on the right side - you can directly edit the center, tile coordinates, zoom level, and quad representation; the map will recenter accordingly   - values out of range (according to the current zoom level if applicable) will be rejected; if necessary change the zoom level before you enter tile coordinates - choose regions by adding / removing the red highlighted tile (this will update the list of tiles (in quad representation); also try removing subtiles)   - the region corresponding to the current tile list is highlighted in white - you can directly edit the tile list (quads are separated by anything not equal to 0, 1, 2, or 3); the map will be updated when leaving the tile list text box   - the list will possibly be simplified (e.g. tiles 10, 11, 12, and 13 are replaced by tile 1) - the bounding box is updated after any change of the tile list; click the "Zoom to" button to center the map according to the bounding box - the content of all boxes (also those that are read only) can be marked, copied, and pasted to any text editor Generating overlays (format kmz for use in Google Maps, Google Earth, or any navigation device or app supporting the kmz format): - kmz formats are generated in 4 steps that all depend on each other and on the tile list selected above - changing values in one section will possibly update values of other sections, so it's best to set all options before generating anything - generating URLs:   - you need a URL scheme where to download the tiles; to find some sample URLs of the tiles, surf to any page displaying tiles of that provider,     display media information of that page (e.g. on firefox click on the icon left to the URL, choose more information, and then media),     there you'll find among others the tile URLs; replace x/y coordinates, zoom level, and quad representation by [[XX]], [[YY]], [[ZZ]], and [[QQ]], resp.   - the zoom level you specify here is the zoom level of the tiles to download   - the number of tiles given is calculated from the list of quads, the specified zoom level, and how tiles are going to be assembled (see below)     - it's the number of tiles needed at the given zoom level to cover the region defined by the list of quads     - it's also guaranteed that the tiles needed for the assembling below are included - e.g if you plan to download tiles from       zoom level 18 and are going to assemble 32x32 tiles, the URL list will include all 1024 sub tiles needed for assembling the tile       that will correspond to a tile of zoom level 13 (but with much more details)   - the generated list is a list of URLs, so it's no command batch file to be executed, but to be used as input for some download tool (e.g. wget, see above)   - fun part: you can also use this function for some quick calculations; try for example "[[QQ]]=[[XX]],[[YY]] at zoom [[ZZ]]" as URL scheme - renaming downloaded tiles:   - this will generate a command batch file that has to be executed on the command line   - the "from part" is derived from the URL scheme (edit if necessary), the "to part" can be edited to your needs   -
Known Bugs / Limitations: - The bounding box is determined by using Google's class LatLngBounds and its method union. Around 180 degrees longitude   the values of the bounding box may get wrong (e.g. bounding box of quads 02, 03, and 13),   thus the bounding box in the resulting doc.kml may have to be adjusted by hand;   Google's union tries to determine the smallest enclosing rectangle, but probably by extending the bounding box with   the southwest and northeast corners individually, not taking care of the rectangle that's to be included. - When assembling 32x32 tiles the command line gets too long, so we first assemble each 4x4 and then 8x8 of those
Disclaimer: I'm not responsible for whatever you do with these scripts. So download only from servers that allow using the tiles (e.g. openstreetmap).
Copyright: © by Stefan Lewandowski, except code for conversion of tile coordinates to and from geographical coordinates taken from this example Feel free to use and adapt the scripts to your needs.

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Kontakt	Stefan Lewandowski Kaindlstr. 38 70569 Stuttgart Deutschland madeira (at) warumauch (dot) net
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