Global Mapper Pro

Convert Meters to Feet?

Roger Edrinn
Roger Edrinn Global Mapper UserTrusted User
edited April 2011 in Elevation Data
I downloaded a huge placename text file which I opened in GM . . . no problems. The default elevation values are in meters, I need them in feet.

I searched the manual for convert, lot of hits, but no help. I tried the option button in the layers manager dialog. I tried the configuration dialog, elevation tab. No obvious solution.

So how do I convert meters to feet for these 10,000 places?

Thanks

Comments

  • global_mapper
    global_mapper Administrator
    edited December 2007
    Currently the only way to convert the elevation attribute units for vector features is to export the data to a Simple ASCII Text file and check the box to include an elevation value, then reload that file and use the Point Offset/Scale button to specity the appropriate Z scale factor to cause the unit conversion that you need.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited December 2007
    Thanks Mike,

    Looks like my old way of opening the text file in Excel and making the conversion is about the same.

    That and both our teams lost today, oh well.

    Thanks
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    Same problem, 3-years later, any better solution in GM 11.02?
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    Perhaps a script could do the meters to feet conversion if the script language allows math operations?

    Adding to the wish list, would it be not be possible in the Layers > Options dialog to add point type (Airport, Basin, etc.) recognition if I pointed to the appropriate column in the shapefile?

    Thanks
  • global_mapper
    global_mapper Administrator
    edited June 2010
    Actually there is a slightly better way. If you setup your elevation display/export units on the Vertical Options tab of the Configuration dialog to metric or statute, your elevation values should automatically be converted on export to the selected units when exporting to a 3D format.

    For the type assignment, if your vector file has an attribute matching a known type attribute in Global Mapper, like GM_TYPE, LAYER, GM_LAYER, etc., then you should automatically get the types assigned based on matches against the built-in type names in Global Mapper.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    Actually there is a slightly better way. If you setup your elevation display/export units on the Vertical Options tab of the Configuration dialog to metric or statute, your elevation values should automatically be converted on export to the selected units when exporting to a 3D format.
    Well, since I export to MP text files, MP doesn't sound like a 3D format to me. Besides, I never export a single layer, rather a composite of many layers, one of which is contours, I see problems ahead. Seen many a 50,000 foot contours in my exports.
    For the type assignment, if your vector file has an attribute matching a known type attribute in Global Mapper, like GM_TYPE, LAYER, GM_LAYER, etc., then you should automatically get the types assigned based on matches against the built-in type names in Global Mapper.
    Not following you here. Currently my shapefile has all the point types in the column Feature_CL, can I rename that column GM_TYPE and during import of the shapefile GM will find all the matches?

    Thanks for the help.
  • global_mapper
    global_mapper Administrator
    edited June 2010
    The MP format has its elevation units controlled by its header and some elements define a particular elevation unit. For MP files (well all files really) what is important is that your import files have the correct elevation units selected for the layer, otherwise they will be improperly converted on export.

    In earlier Global Mapper versions you could setup the elevation units interpretation for a vector layer on the Projection tab of the Options dialog for the layer, but just yesterday I moved that to the main options tile for a vector layer (just below where you select the elevation attribute), so the elevation units interpretation for a vector layer should now be more obvious and easy to change.

    Yes if you rename your column with the feature type names in it to GM_TYPE, the types should automatically be assigned if the match the names of types already in Global Mapper.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    Yes if you rename your column with the feature type names in it to GM_TYPE, the types should automatically be assigned if the match the names of types already in Global Mapper.
    That worked. :) Except GM did all the easy ones leaving me to figure out buckets for all the obscure types. ;)

    As to the elevation, since I had to open the file anyway to change the name, it was just as easy to delete the columns of crap and multiply by 3.2808399.

    All done, many thanks.
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    My GM 11.02 is dated June 9.

    When I look at my points in GM, they have a compound name (Name, xxx Ft) created using the Multiple named feature in the Option dialog. However, the complied img file have this name: (Name, xxx Ft, yy ft) where the yy is clearly the meter value.

    Clearly, GM is attaching this ", yy ft" string to the MP text file. How?
  • global_mapper
    global_mapper Administrator
    edited June 2010
    What is the MP type of your features? Several types (like some topo-type points) will automatically append the elevation of the feature to the label when the feature is displayed. Global Mapper just provides the label you have set and the elevation, then the unit itself automatically appends the elevation value provided to the label in the correct units when displayed (I know because I wrote the code for the Garmin units that does this). I would suggest removing the elevation from your compound labels in Global Mapper and just let the unit's automatic labeling with elevation work.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    They're geographic point types, gap, school, peak etc. I don't want the yy meter value and I don't want ft, I want Ft. The elevation values on the contours are correct.

    Basically, I want WYSIWYG, no surprises.
  • global_mapper
    global_mapper Administrator
    edited June 2010
    I can't control what the unit does with those types as different units will do different things. However, the fact that you are getting the meters value displayed as feet on the units makes it look like the elevation units are being mis-interpreted for the features when the MP file is generated. Do you have the elevation units set to feet for the vector layer so that any elevation values without a unit indicator are interpreted as feet?

    Once you have that setup right you should remove the elevation from the label to avoid duplicating this on the unit (something that is automatic for those types and out of Global Mapper's control using those types). Building it into the label is not what you want anyway because then when users switch to metric unit display for elevations your pre-built labels would stay showing feet rather than automatically converting to and displaying the elevation as meters based on the user's settings.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    That was a bit of an Ah ha.

    I'll be back when I do more testing.

    Thanks
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited June 2010
    Mike,

    Well we both had bugs today. Mine was in my head. This phrase "what the unit does" finally made it all click. I never realized that elevation is a dynamic value capable of being changed by the "unit". In this case Mapsource, same for a GPS. When I switched to meters in Mapsource, it all made sense. Both the contours and point elevations changed, so I did indeed want to specify meters for these points and set feet in Mapsource.

    Ah Ha!

    Thanks
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited April 2011
    Yes if you rename your column with the feature type names in it to GM_TYPE, the types should automatically be assigned if the match the names of types already in Global Mapper.

    Revisiting this question.

    GM picks up the GM_TYPE column and assigns a correct feature type to the known point types. However it does not pick up the Feature Name column, but it does have an attribute for each point called Feature name.

    Do I need to use the Layer Mgr > Options to assign the Feature name?

    I'm using GM11, could use GM12 if it makes a difference.

    Thanks
  • Roger Edrinn
    Roger Edrinn Global Mapper User Trusted User
    edited April 2011
    Discovered that if I rename the column from Feature Name to Name, all is well.

    Thanks
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