Global Mapper Pro

Crop exported data to state boundary

-Oz-
-Oz- Global Mapper User
edited December 2008 in Vector Data
Hi,

I have a bunch of data (federal lands) that I want to crop along the state boundary. I have the boundary as both a line and an area and I can't seem to get it to crop the data. I only want what is actually inside the state boundary.

How do I go about doing this?

I tried selecting the area (identify tool), then going to export vector data and I wanted to select "crop to selected area feature(s)" but it is grayed out.

Thanks

Comments

  • global_mapper
    global_mapper Administrator
    edited February 2008
    There is not currently any support for automatically cropping line and area features to a existing area feature. That functionality is only supported for cropping raster and gridded elevation layers.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • kartoone76
    kartoone76 Global Mapper User Trusted User
    edited December 2008
    The crop to area feature works great for me when selecting only a single area feature, but if I select multiple features I run into a problem where the data is not being exported at all.

    Here are the steps I have taken to recreate the problem

    1. Load large approx. 835 MB gmg elevation data file
    2. Load shapefile with several area features for the coastline of california and islands
    3. Click the digitizer tool, click edit->select all features
    4. Select Export->Raster and Elevation->JPG from the menu
    5. On tab 1, change the export spacing in arc degrees to 0.001(X), and 0.001(Y)
    6. On tab 2, leave defaults
    7. On tab 3, select "crop to selected area(s)" in the export bounds dialog
    8. Click OK

    The result is an exported JPG that only has the elevation and scale showing and everything else is the default background color.

    If I use the same exact data sets (just two datasets) without even unloading them and then select a single area feature instead of multiple features, the export works fine and I get the exported JPG cropped with all data (elevation data) showing within the cropped bounds. Is this a bug or am I doing something wrong?

    The datasets are huge if that might be a factor ... the resulting blank jpg has a resolution of 10,278 x 9,475 pixels

    I have attached four screenshots to help illustrate the problem:

    Screenshot 1 - the screenshot of global mapper showing the selected area features
    Screenshot 2 - the export dialog (tab 1)
    Screenshot 3 - the export dialog (tab 3)
    Screenshot 4 - the resulting exported jpg

    (these are zipped together)

    Thanks in advance for your help!
  • global_mapper
    global_mapper Administrator
    edited December 2008
    Someone else had the exact same problem yesterday and we were able to get it fixed. I have placed a new build at http://www.globalmapper.com/global_mapper10.zip with the fix for you to try. Simply download that file and extract the contents into your existing v10.xx installation folder to give it a try.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • kartoone76
    kartoone76 Global Mapper User Trusted User
    edited December 2008
    I extracted it and it works great for multi-area feature selections... Thanks! Check out these statistics for doing the export ... I saw that you had posted something about a "map catalog" to boost performance because of a cacheing issue.

    x/y spacing: 0.005, jpg output resolution:2056x1895, time: 4 seconds
    x/y spacing: 0.004, jpg output resolution:2570x2369, time: 5 seconds
    x/y spacing: 0.003, jpg output resolution:3426x3158, time: 6 seconds
    x/y spacing: 0.002, jpg output resolution:5139x4738, time: 10 seconds
    x/y spacing: 0.001, jpg output resolution:10278x9475, time: 476 seconds (7 minutes 56 seconds)

    What do you think might be causing the severe performance degradation when using the 0.001 spacing? Is it a cacheing issue? Is there any way to fix that? It just seems odd to bog down so bad when going from 0.002 to 0.001 - ideally i'd like to export at 0.0002 (or approx 50,000x45000 pixels) for hi-res printing, but I would suspect that would take days to complete.

    Also, if its a cacheing issue, I wonder if a core i7 or an AMD processor both that have the increased memory bandwidth that comes from not using a front side bus would help?
  • global_mapper
    global_mapper Administrator
    edited December 2008
    When you render vector data to a raster format the entire imagery has to first be rendered in memory. I'm guessing that when you hit 0.001 resolution the allocated memory chunk can no longer fit into VRAM all at once and gets much slower to write to. I imagine you would fail altogether if you got much larger.

    What I would suggest is using the Gridding tab to break your export into smaller pieces for the very high resolutions. Then when the export is done bring those pieces back into Global Mapper and export to a single new raster file. Since the rasterization is already done the large export image won't have to be built all in memory and you won't have the memory issue.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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