Global Mapper v25.0

difficulty sorting vector data by attribute?

aawilson
aawilson Global Mapper UserTrusted User
edited December 2010 in Vector Data
I am using the Search By Attribute tool to select forest stands with certain attributes (the equivalent of a "query"in ArcView) for display by volume, cover type, etc. I want to be able to export a subset of the data so it is displayed as a separate data file, then assign unique fill and styles to that layer for making a map. I have found a method to do this but the method is a bit tedious...

I have been successful if i do the following: double-click on the top of each attribute column to sort the attributes one by one, manually deleting the stands that dont meet my criteria. Then i click the Select All button, then right click and select "Zoom to Selected Features". I then have a separate layer that i can export as its own shapefile.

However, it is a lot of work this way sometimes if there is alot of data. Another downfall is the way the data i am using is displayed. If an attribute has values that could be one, two or three digits, the one and two digits values are lined up on the left of the column instead of the right, making sorting the data a headache. Instead of the data being in sequential numerical order from bottom of column to top, or vice versa (eg, 0 to infinity), the data that is only one or two digits ends up being scattered amongst the three-digit data, requiring me to scroll through all the data to find this stuff so i can delete it. Ex:

121
13
131............the 13 value is lost amongst the other numbers, instead of being near the top of the list.


It would be easier to use the "Search by Criteria" window to repeatedly query the data that i want, attribute by attribute (thus avoiding the task of manually deleting stands that dont meet the search criteria) but cannot seem to get only these stands to show up in the control centre as their own data file. The selected stands are shown on the map but still are part of the original data set, not separated from it so export can be done. The Zoom to Selected Features option does not seem to work the same way when i search the data using this method.

I may have just failed to find the proper method, it seems like this should be possible?

Comments

  • global_mapper
    global_mapper Administrator
    edited October 2010
    For sorting, if you have the search type set to 'Numeric' when you sort the columns then the sorting will be done numerically rather than alphabetically. that should give you the sorting you want.

    For exporting just a sub-set, I would suggest selecting them in the search results window, then right-clicking and selecting to copy to the clipboard, then open a new Global Mapper instancing and use Ctrl+V to paste the results then export those.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • aawilson
    aawilson Global Mapper User Trusted User
    edited October 2010
    Thanks Mike, if i switch from "text" to "Number" this seems to fix my sorting problem regardless of what method i use to sort the data.
  • falqn
    falqn Global Mapper User Trusted User
    edited December 2010
    Hi,
    I have similar problem. I'm adding length attribut by option Add/Update Measure Attributes. GM is adding this attribute and values but in "km" or in "m" for objects shorther than 1 kilometer. I want to delete smallest objects, but when I'm sorting with length column I have for exmaple:
    110 km
    100 km
    99 m
    98 km
    When I try to search in text or numeric mode the problem is the same. Is this a bug or I'm doing something wrong?
    Best regards
    Wojtek from Poland
  • global_mapper
    global_mapper Administrator
    edited December 2010
    Wojtek,

    What you need to do is switch to the Measure Tool, then right-click and check the option to always use base units. Then when you add length units they will never switch to larger units like 'km', but will stay in the base units (like 'm') so you can sort by them.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com