Global Mapper v25.0

Controlling the appearance of a point or line with attributes

DC Kelley
DC Kelley Global Mapper UserTrusted User
edited July 2011 in Vector Data
I a have a large number of points will I will import to a layer of their own (they represent rapid GPS positions as well as speed, velocity, acceleration and a host of other meta data) and I want do more then simply "plot points" for the data sets.

What I need to do is adjust the point style used (shape, color etc) based on some of attributes of the imported data. I have the attribute set importing (child's play for GM), but may need to pre-process my data to get the precise values I need (it is not clear what functions I can add to the point display control logic).

I see some layer-level dialog tools for this, but the am not clear how far I can go other then to map a point type to an attributes and use attributes in the textual labels that are displayed. First Question: Can you got beyond just picking a predefined shape and/or color in this?

As a concept, if a position has a velocity and heading angle associated with it, it would be nice to anchor a point at that location and then build a short arrow in the heading direction and have it's length be proportional to the velocity value and select a color based on its acceleration values. Related Questions: Am I pushing my luck here? Can this be done with points or is this really a line segment use? Is this another topic that needs the API and some programming to be solved? Any prior examples to point to?

Comments

  • global_mapper
    global_mapper Administrator
    edited July 2011
    For point features you are limited to using a existing point symbol (either built-in or any custom symbol that you add). There isn't any support for creating a line anchored at the point going in some direction or of a particular length. You would have to have added symbols with the desired characteristics and use those, like maybe have a collection of point symbols with arrows pointing off in different directions, then set those up based on the attribute values.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • DC Kelley
    DC Kelley Global Mapper User Trusted User
    edited July 2011
    So the short answer on this may be that the use of points is limited to selecting from predefined things and nothing "dynamic" as such is allowed. I can cope with that just need to understand it.

    So back to perhaps using lines and scripting as a solution to this need? I presume I could take a raw CSV data set composed of point/vel/accel and develop a set of line segments with some basic first order model for the expected movement to get the "other" end point to use, then select from a much small number of lines types. That part is grossly straight forward, but..

    Then the question becomes, I presume there is a way in the tool to import line segments with either start-end point sets or a start-distance-bearing method like what I see for line entry. Is this a valid presumption? I do not see any line import examples (ie gross format expected or how "break feature on" is to be used) to test the hypothesis on. I can tell from the dialog box that tool can take mixed line and point items, but a fragment to ape as a test would help

    Repeating from before... Related Questions: Can this be done with points or is this really a line segment use? Is this another topic that needs the API and some programming to be solved? Any prior examples to point to?

    And just to add another side thought to this complex topic thread, when the CSV import occurs and all these attributes are created, is there any way to provide the preferred name to be used, such as in the first line of data?
  • global_mapper
    global_mapper Administrator
    edited July 2011
    The dynamic abilities of the point styling would be if you setting the styling using custom shape symbols with a specified color and size. If you specify to interpolate between values and consecutive values are custom shapes then the shape colors and sizes will be interpolated between the bracketing style values. Normal symbols don't work that way though.

    See http://www.globalmapper.com/helpv12/GenericASCIIFormat_Instructions.doc for information and examples on how to import different types/styles of areas, lines, and points from simple text files using the File->Open Generic ASCII Data File menu command.

    You really need to use line segments for a reasonable solution to creating directional lines at a series of points.

    For CSV import you can specify the attribute names in the first line, just also check the option on the ASCII import that the first line is a header column.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • DC Kelley
    DC Kelley Global Mapper User Trusted User
    edited July 2011
    That seems like the ticket, let me curl up away from a PC and do a bit of reading from the documents you just pointed me at and try and make a test case to try. Sorry to post what I should have found on my own. The "tutorial" video titled "Importing ASCII files into Global Mapper" may be a bad link, it goes to a demo with the title "Max Slope and Create Line from Selected Points" when clicked and seems off topic to me.
  • global_mapper
    global_mapper Administrator
    edited July 2011
    The video tutorial link just takes you to the general video tutorial page at http://www.globalmapperforum.com (http://www.globalmapperforum.com/tutorial.html), which video appears on top seems to be random.

    For ASCII files, you might also be interested in http://globalmapper.com/helpv12/GenericASCIIFormat_FieldOptions.doc which describes some of the recognized field names and how they work.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • DC Kelley
    DC Kelley Global Mapper User Trusted User
    edited July 2011
    Mike thanks again for your help. I have both points and line styles data importnig from the same file depending on how I set the dialog options now.

    My current issues concern mostly the different forms of attribute treatment, so I will start another thread on that issue.

    But one concern remains. Can lines be imported in any from other then sets of points? In other words, is there an import method that allows a bearing and distance style of import here? As survey crews love to record this way in the field when moving off a monument, I am sure other have asked for this but so not see it anywhere.
  • global_mapper
    global_mapper Administrator
    edited July 2011
    While you can't directly import from a file with anything other than points, you can use the Distance/Bearing/COGO line input option of the Digitizer Tool to provide a start point, then provide distances and bearing from that to define a path, like from a survey.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com