Export Web Format

MykleMykle Global Mapper UserPosts: 452Trusted User
edited July 2013 in Technical Support
Export Web Format

1. Does GM have a method by which a grid of Web Format tiles can be displayed?
2. Do the Export Options have a choice for writing only tiles filled to tile bounds?

I have created several maps in Web Tiled format that work well in applications that support that format.

I am now attempting to create a larger and more complex map that contains a background of DRG Geotiff files overlaid with manually scanned and registered maps covering parts of the overall area. This map is too large to work with at one time. The overlaid maps are not continuous, with the DRG maps providing infill coverage.

Exporting separate tile sets, then combining them into one structure does work, but incomplete border tiles overwrite complete tiles. The extent of the blank areas varies with the zoom level. Tiles along the borders can be edited, in Photoshop for example, but this is a tedious process given the number of levels and tiles, and Photoshop may change the index mode so that a color may change. I am manually overlaying a complete tile with an incomplete component map border tile, resulting in a tile that is complete and shows the component map content. I don't want to do this for very long!

Being able to display a grid of tiles (the grid would display the tiles for a selected zoom level) would help retrieve particular tiles that may need attention, especially if the grid is labeled by folder and tile numbers. A lat/long grid can be displayed, but the tiles have different widths depending upon latitude unless the Web Format is using a rectangular projection.

If tile sets can be exported so that any partial tiles are NOT written, then the set of tiles can be copied into the master map structure without any blank areas showing along the border of the component map.

I might need to export one level at a time, but that would be a lot more efficient than hand-editing the border tiles.

The Web Format structure provides for very large maps (even the entire world, well beyond my area of interest!), and only the tiles needed to fill the display are loaded and shown.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited June 2013
    Yes you can add a new custom tiled source on the online source dialog (use OSM, TMS, or Google Maps tile type, depending on how they are laid out). You can specify a local file URL rather than a web URL to work with a local source.

    If you export tiles to PNG images then the edge ones should be transparent so you can merge them with other data sets.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation
  • MykleMykle Global Mapper User Posts: 452Trusted User
    edited July 2013
    Thanks Mike,

    Using a new custom tiled source does work to import these maps. While I did not play long with the map, I was not able to configure the tiles to use transparent edges.

    I chose to re-do the entire map consisting of about 100 DRG with matching DEM, then overlaying with custom maps covering part of the total area (it's nice to have a 64-bit version of GM !!). Several features of Global Mapper were employed to improve the resulting map, especially the ability to set a particular color to be transparent on each custom map. Simply setting white to transparent, for example, can result in transparent white areas within the map as well as the borders. Editing each custom map and painting the borders with a unique color provides a method to limit the transparency. Global Mapper provides the tools to identify that color with zero tolerance. Perfect.

    The resulting maps appear as intended, so I don't have any requests that need to be addressed immediately.

    For your To-Do List however ...

    My original questions remain:

    1. Does GM have a method by which a grid of Web Format tiles can be displayed?
    2. Do the Export Options have a choice for writing only tiles filled to tile bounds?

    A grid of Web Format tiles (at a specified level) would be helpful while working with maps to be exported in this format. A lat-long grid is not appropriate.

    The second question is more of a practical issue. If/When I update any of these maps, where I will work on only one portion of a map, it will be difficult to export only a set of tiles that can be overlaid on the existing tile structure. The edge tiles will have non-transparent coverage on the outside of the new work. Again, I didn't play with it very much so may be missing something easy to ensure the outside edges are transparent outside of the map.

    These maps require many hours to export tiles at a variety of map levels. So working with a small area will be more effective if the set of updated tiles can be copied over the original without including any blank edges.

    My work-around was to physically delete columns of tiles that contain an edge (each column is a separate folder in the Web Format). Then, since all tiles for one row are named the same in each column, I searched all columns for all tiles with the same number that contain an edge and deleted them. Tedious, but effective. The resulting set of tiles can be seamlessly copied over the original map tiles.

    So, this work could be avoided if GM was able to specify that all of the tiles to be written are required to be filled to the tile bounds. Or, from a different angle, all tiles must lie completely within the export boundary. I suppose that some users will have irregular boundaries that will complicate this procedure, so I'm not sure how to implement this request.

    Many thanks!
    Mykle
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2013
    Mykle,

    I have added a new option to the web exports dialog to only export tiles that are fully covered by the specified bounds (only bounds are checked, not any irregular areas yet). I have placed a new build at http://www.bluemarblegeo.com/downloads/global-mapper/global_mapper14.zip with the latest changes for you to try. Simply download that file and extract the contents into your existing v14.xx installation folder to give it a try. If you are using the 64-bit v14 version there is a new build at http://www.bluemarblegeo.com/downloads/global-mapper/global_mapper14_64bit.zip .

    You should be able to use that to only update fully covered tiles in a larger web export data set.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation
  • MykleMykle Global Mapper User Posts: 452Trusted User
    edited July 2013
    Mike,

    I have completed a couple of tests, and the results are as expected. No tiles are written that have any out-of-area content (all tiles are completely filled).

    This additional option will be very useful when updating small areas within a large map in Web Format.

    Many thanks for the time that will be saved in the future during these revisions!
    Mykle
Sign In or Register to comment.