Support for MapObjects by ESRI

[subsurface]

I downloaded MapObjects LT from ESRI to give a labview vi I am working on some GIS functionality.  Things started out well when I placed MapObjects in an ActiveX container, and I easily pulled up maps, zoomed and panned etc.  However I found after a while that a number of properties and methods that were advertised to be present in MapObjects did not seem to be accessible.  For example, I cannot seem to access the search functions that search through a database of items in a map layer. 

Anyone got any suggestions about use of MapObjects LT (and the full version) or any other GIS software that can be integrated into a Labview vi?  There's no useful information in the ESRI forums for MapObjects, and they seem to concentrate their support on VB6.  The prospect of swapping Labview for VB6 fills me with horror...

[TheDillo]

It's odd that advertised functionality would not be present, or not accessible.  It sounds like a MapObjects LT issue.  I'm not familiar with MapObjects LT, after looking on their website I was able to find that the LT version is the lightweight version of the full MapObjects?  Perhaps the functionality you require is not available in the LT verison? 

Have you tried accessing them in VB6?  I'm curious because if it's visible through ActiveX on VB6, it should be visible in LabVIEW. 

[subsurface]

I don't think that it's a LT versus full version issue. I was using a pdf intro guide to the MapObjects LT version and it certainly described the features. I think there may be a workaround for the search problem by loading the database (dbf) file that comes with GIS maps (which come as triplets with extensions shp, shx, and dbf). However I'm pretty much working in the dark however as there's no support for Labview in the MapObjects that I can find (shame on them!). I haven't tried vb6, but the pdf manual discusses it exclusively so I presume it works.

Perhaps a more serious issue came up today. In MapObjects you can add different layers to maps by loading additional shp files. This works fine in the front panel when done manually. Trying to do the same thing programmatically seems impossible. The invoke node in Labview that adds a layer specifies a variant data type but I haven't been able to open it up and take a look. I tried to unflatten the variant data to string and look at the string, but no joy there, the string comes up empty. Using various file reading vi's has so far failed entirely to produce anything that can be converted into variant type and then fed in. Unknown errors pop up. Looks like I'm in for a long haul...

Any further advice is much appreciated and thanks for taking the time.

Subsurface

[TheDillo]

I don't have any advice other than trying it out in Visual Studio, I think that would give you the best idea how they work.

The unknown errors that pop up - what are their numbers and messages?

[subsurface]

I explored a little further with MapObjects LT and managed to get some basic functionality. As there's no help to speak of (documents limited and speak only of VB6) I had to wire things by trial and error. The variant data type in Labview was the main problem as I had no idea (without the helpfiles) what should be wired in to what, so even opening a new layer in a GIS window took me ages. I was trying to wire in the data after opening a shp file and putting the data through the variant converter, but eventually it was as simple as making a reference to the file and sending that in through the variant converter. It seems the Map Object doesn't want the layer data, just it's file name. I found the missing functionality by creating general invoke and property nodes and then using the link to ActiveX object to bring up the dialoogue box where you can find other map objects.

I have a hot tip for anyone reading this who is also trying to get GIS into labview: leave MapObjects LT and download MapWin GIS. It's open source under the Mozilla license and comes with better help (although also only VB6). It has many more functions but the front panel map opening feature doesn't work – one plus for MapObject LT which does work. I guess the arrival of MapWin GIS means that MapObjects won't be developed any further (the full version is expensive). Anyway I now have basic map functionality in my Labview application so I'm happy.

Thanks again for the help Dillo.

Subsurface

[MyronC]

Subsurface,

I'm very new to this whole area - and I'm wondering if I could persuade you to share your VI work with MapWin?  I've downloaded, and installed it.  I've even got the Active X on a VI.  Beyond that, I'm completely lost.  Does the book provide enough information for (very) green newbies?

Any insight, help, or further readings you can suggest would be greatly appreciated,

Thanks

Myron

[subsurface]

Myron - sorry, I was tied up with a bunch of other stuff and didn't get round to looking at your posting till now. I've still got the vis I was messing around with for mapwin. Drop me your email address and I can email a vi over. As for help etc, it's non-existant from mapwin for the LV environment. You just have to experiment until you can get stuff to work. There is no book and it's not very friendly for a newbie I'm afraid.

[MyronC]

subsurface,

my email is mcoleman2 [at] unl [dot] edu.  Thank you very much!!

-Myron

[MyronC]

Subsurface,

I was wondering if you had found time to send those samples?  I've been checking my junkmail as well - I haven't seen any mail.  A better email address is through my work account.  Rather than typing it here for the spam bots to find, all you have to do is search for "Myron Coleman" on google.  The first result is me, I'm with the Agricultural Research Service (ARS).

I appreciate your help - I was thinking I would have to re-code our entire software set in VB 🙂

Thanks again,

Myron

[AlaaShaw]

subsurface

could u plz send me an example for the new "Mapwin GIS" i am looking for using it my email alaa_mohamedy@hotmail.com