MapWindow:UsingActiveX
From MapWindow GIS
The core MapWindow component is the ActiveX control, "MapWinGIS.ocx". This is
an programming object that can be added to a form in Visual Basic, or other
languages that support ActiveX, providing a built-in GIS data map. As
engineers, we have tried to optimize it for use as a fully functional model
interface, not just as a map viewer. This involved speeding up image and grid
display, limiting the amount of redrawing that the user sees, and including
application programmer interfaces (APIs) for low-level access to grid, shape,
table and image data.
The full MapWinGIS ActiveX control documentation is an indispensable resource for learning to use the ActiveX control.
Here is an example of the simplest MapWindow project you can build:
The code that adds this shape file to the map is:
With a shape file layer loaded in the map, the user can navigate the map using
the left and right mouse buttons to zoom-in and zoom-out.
Note that although I said this is the simplest MapWindow project you can build,
I lied. Actually the simplest project would be to just put the map on a form
and compile with no code. Although the program would start with an empty white
box, a user could grab any shape file or geo-referenced bitmap and drop it in
the map, and the map will display it.
The MapWindow core component can be more interesting when you add a few layers
of data to it and provide other means for navigation.
For example, with just a few lines of code, the project above can be extended
to display this:
The code for the above applicaton is:
Granted, these are very basic demonstrations, but the idea is to let you get a
taste for what the control can do and how it can be used.
Additional functions of the core component ActiveX control include:
- Open, create, edit, and save geo-referenced image, grid, shapefile, triangulated irregular network (TIN), and dbf (shape attribute) data directly;
- View, label, color, highlight, shape file data in the map;
- Perform spatial queries on the data;
- Search for features with specific attributes;
- Dynamically edit the spatial data and immediately see the changes in the map;
- Interact with the data through the map;
- Build TINs from Grids, Images from Grids, Shape files from TINs and Grids, Grids from Shape files, etc.
- Much, much, more...
