Knowledge Base

KB10379 - Method to keep a shape the same size regardless of the zoom scale.

There is no easy way to do this. You would have to use Reset, AddPart, and AddPoint to reconstruct the shape on any given scale. Better is to use a symbol/icon for this purpose. ...

Modified: August 05, 2015

KB10378 - Measurement units for Params.Labels.Width and Params.Marker.Size.

If there is a " + " sign before the number, the label width or marker size is defined in TWIPS (1/1440 of an inch). If there is a " - " sign before the number, the label width or marker size is defined in pixels. ...

Modified: August 05, 2015

KB10376 - Using the DK-ActiveX control to modify the layer extent.

The Extent property is an object. The proper method to assign values is as follows: Dim GisUtils as New XGIS_Utils ll.Extent = GisUtils.GisExtent( 0, 0, 100, 100 ) ...

Modified: August 05, 2015

KB10369 - Add a new field to a layer in a TatukGIS Project.

An example of adding a new field to the layer: ll.AddField( 'name', gisFieldTypeString, 256, 0 ) ; and then shape.SetField( 'name', some text ) ; str := shape.GetField( 'name' ...

Modified: August 05, 2015

KB10370 - Identify a point, line, or area in a shapefile.

Identifying can be understood two different ways: as identifying by mouse click, then refer to the DK sample Locate in DK sample set #1, as identifying a shape type, refer to the DK ShapeType property, or you can also test in the following manor: if shape is TGIS_ShapePoint then ..... ...

Modified: August 05, 2015

KB10372 - Location of the GISSamplesDataDir variable.

This is stored in the TatukGIS.ini file location in the Windows directory. A call to INI is provided in GisSampleDataDir. Other files or directories can be stored to this file as well. ...

Modified: August 05, 2015

KB10367 - Get pixel widths and pixel heights of JPEG image file.

Refer to the DK properties BitWidth and BitHeight for the pixel width and height information. Refer to the DK properties Extent.ymax and Extent.xmin for the easting, northing, westing, and southing information. ...

Modified: August 05, 2015

KB10363 - Anchor a text label to a fixed position where there is no specific vector.

To make a label display on a map by itself without any visible vector object, simply associate the label with a point vector at this place on the map that is set to be fully transparent. ...

Modified: August 05, 2015

KB10337 - Mouse Wheel support in the TatukGIS Project.

Delphi supports the Mouse Wheel only as a focused control. So you can proceed by calling GIS_ViewerWND1.SetFocus. But better is to add OnMouseWheelXXX events on your form and redirect such events into the GIS_ViewerWND control. For example, this code shows how to add zoom-in on a mouse wheel event: procedure TForm1.FormMouseWheelDown(Sender: TObject; Shift: TShiftState; MousePos: TPoint; var Handled: Boolean); begin GISMouseWheelDown( Sender, Shift, MousePos, Handled ) ; end; procedure TFo ...

Modified: August 04, 2015

KB10341 - Auto-center feature in the TatukGIS Project.

If the auto-center feature is set to True, then the screen will be re-centered upon each click, edit, etc. event. The default TatukGIS Project auto-center value is True, so if you want to override this with your own methods for handing clicks on the map, use the following to turn it off: GIS.AutoCenter := False ; ...

Modified: August 04, 2015

KB10353 - Defining a style in the DrawScope procedure using an ini file.

An example of calling the DrawScope procedure looks like the following: ll.DrawScope("STANDID=34156", "flush"). To a style (such as color), define this in your project/ini file section, or do it programmatically: [TatukGIS Layer] Area.Color=GREEN [TatukGIS Layer 1] Style=flush Area.Color=RED or Aera.Color=$0000EE (GBR) =100:0:0 Note that the style called "selected' was predefined. ...

Modified: August 04, 2015

KB10347 - Registration/World file created with other GIS software product is not visible.

Some (non-TatukGIS) software products assign crazy dates, such as thirty years in the future, to World Files generated during rectification, which the Borland code (for some reason) in the DK does not accept. Check if your TFW (JGW, etc.) file has a logical date. If not, change the date to something reasonable, and try again to open the file in the DK or other TatukGIS product. ...

Modified: August 03, 2015

KB10349 - Error (DB.OBJ not found) when compiling *.bpk package under Borland C++Builder.

Add the DBRTL.BPI and DBEXPRESS.BPI files to the "requires" list. ...

Modified: August 03, 2015

KB10356 - Restore the last map extent upon reopening a project.

Using TGIS_Viewer.VisibleExtent will save the zoom level and extent position into the next session. Save the VisibleExtent before exiting and set this just after reopening the project. ...

Modified: August 03, 2015

KB10355 - Calculate centroid point of an irregular shaped polygon.

The DK and Editor support two possibilities: Calculate the true centriod position, regardless whether or not it lies within or outside the polygon area. Use - TGIS_Shape.Centroid Calculate the point within the polygon area closest to the true centroid position, to guarantee the calculated point is within the polygon boundary. Use - TGIS_Shape.PointOnShape It is possible to use a given point to reposition (move) an irregularly shaped polygon, such that the point becomes the centroid of the polygon ...

Modified: August 03, 2015

KB10354 - Calling TGIS_ControlLegendForm from the code.

Use the following code: function TGIS_ControlLegendForm.Execute( const _layer : TGIS_LayerAbstract ) : Integer ; ...

Modified: August 03, 2015

KB10348 - Display a point from a database on the map.

Create a TGIS_LayerVector layer and then, on each database query, add the following code: layer.RevertAll ; // will reset layer status while not ors.Eof do begin while not ors.Eof do begin shp := layer.CreateShape( gisShapeTypePoint ) ; shp.Lock( gisLockExtent ) ; shp.AddPart ; shp.AddPoint( GisPoint( ors.Fields['X'] , ors.Fields['Y'] ) ); shp.Unlock ; shp.SetField( 'somefield', ors.Fields['somefield'] ) ; ors.MoveNext ; end ; end ; ...

Modified: August 03, 2015

KB10344 - Creating a line feature from GPS points.

Step one - create a line: shp := layer.CreateShape( gisShapeTypeArc ) ; my_uid := shp.Uid ; shp.Lock(1) ; shp.Reset ; shp.AddPoint(my_point_1 ) ; shp.AddPoint(my_point_2 ) ; shp.AddPoint(my_point_3 ) ; ... shp.Unlock ; Step two - add a point on GPS update: shp := layer.GetShape( my_uid ) ; shp.Lock(1) ; shp.AddPoint(my_point ) ; shp.Unlock ; ...

Modified: August 03, 2015

KB10342 - Add a pie-piece shaped object to map layer.

There are two options for creating pie-piece shaped (or any other shaped) objects in a DK application: 1) Draw this on your own by rendering the pie-piece shape using a series of lines, like this: shp->Lock() ; shp->Reset() ; shp->AddPoint( GisPoint() ) shp->AddPoint( GisPoint() ) shp->Unlock() 2) Override OnPaintShape event (See samples #1 BitmapFill) ll->OnPaintShape = PaintShape ; void __fastcall TForm1::PaintShape( const TObject *_sender, const TGIS_Shape *_shape ) { TPoint pt ; ...

Modified: August 03, 2015

KB10338 - Adding a new point, line, or polygon shape in Visual Basic.

Create a Point: shp = layer.CreateShape(XgisShapeTypePoint) shp.Lock(1) shp.AddPart() shp.AddPoint(ptg1) shp.Unlock() Create a Line: shp = layer.CreateShape(XgisShapeTypeArc) shp.Lock(1) shp.AddPart() shp.AddPoint(ptg1) shp.AddPoint(ptg2) shp.Unlock() Create a Polygon: shp = layer.CreateShape(XgisShapeTypePolygon) shp.Lock(1) shp.AddPart() shp.AddPoint(ptg1) shp.AddPoint(ptg2) shp.AddPoint(ptg3) shp.Unlock() ...

Modified: August 03, 2015

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