[Shapelib] Re: Shapelib Digest, Vol 46, Issue 3

Joaquin Perez Valera joaquinperezvalera at gmail.com
Mon Feb 18 15:51:09 EST 2008


Hi Tom

Well, I'm working with Dev-C++
I compile and run the code, and the compiler creates a myprogram.exe file.

When I work with myprogram.exe from the command line
I can give a name of the new file. The program creates the shapefile, adds a
column in the dbf file.
And after it returns the number of columns in the dbf.
Then the programm crashes and windows sends the message:
"myprogram.exe has encountered a problem and needs to close."

and I suposse the problem is in my code.

Well, Thanks for your attention.





sorry - I missed that you actually do have first and last elements the
same of your vertex arrays :)
But could you please write down where the error appears and what kind of
error it is?



2008/2/18, shapelib-request at lists.maptools.org <
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> Today's Topics:
>
>    1. Adding a polygon to a shapefile (Joaquin Perez Valera)
>    2. Re: Adding a polygon to a shapefile (Tom Kazimiers)
>    3. Re: Adding a polygon to a shapefile (Tom Kazimiers)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 17 Feb 2008 16:30:21 -0600
> From: "Joaquin Perez Valera" <joaquinperezvalera at gmail.com>
> Subject: [Shapelib] Adding a polygon to a shapefile
> To: shapelib at lists.maptools.org
> Message-ID:
>         <79a4e0710802171430y7dbad9c0p34780e668e3546ff at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi
>
> I can create shapefiles and they are valid when I work with ArcCatalog.
> But
> the shapefiles are empty.
>
> Now I'm trying to add objects to my shapefile. I want to add polygons.
>
> First I create a shapefile and a dbf file with an a simple column. Then it
> becomes valid for ArcCatalog.
> Then I create 2 arrays of 7 elements X[7] and Y[7], and give a valor to
> each
> element. Seven elements because
> I want to draw a polygon of six vertices.
>
> After it I use psObject = SHPCreateObject to create my polygon and after
> SHPWriteObject( hSHP, -1, psObject ); to write it
> in my shapefile.
>
> It's obviously that I'm doing something wrong.
> But I don't know what.
>
> Can somebody help me or say me what I'm doing wrong?
>
> Thanks.
>
>
> [CODE]
> #include <iostream>
> #include <cstdlib>
> #include "shapefil.h"
> #include "string.h"
>
>
> using namespace std;
> int main()
>
> {
>     SHPHandle    hSHP;
>     DBFHandle    hDBF;
>     int        nShapeType,   nWidth = 3, vertexcount, *panParts, ShapeId,
> nParts;
>
>     string  shape_name, Col1;
>     Col1= "Column";
>
>     SHPObject    *psObject;
>
>
>     cout << "Name of the new Shapefile" << endl;
>     getline(cin,shape_name);
>
>     cout << "The shapefile is: " << shape_name << endl;
>
>     //Here I define the type of shapefile, the 5 is for a polygon.
>     nShapeType=5;
>
>
>     hSHP = SHPCreate( shape_name.c_str(), nShapeType );
>
>     hDBF = DBFCreate( shape_name.c_str() );
>
>
>     cout <<"The shape has "<< DBFGetFieldCount( hDBF ) <<" columns" <<
> endl;
>
>
>
>     DBFAddField( hDBF, Col1.c_str(), FTInteger,   nWidth, 0 );
>     cout <<"Now the shape has " << DBFGetFieldCount( hDBF ) << " columns";
>
>     //At this point the shape is valid for ArcView
>
>     //Here I define an array of seven elements and I'll give a coordinate
> for each element
>
>     double X[7], Y[7];
>     X[0] = 220764;
>     Y[0]= 2343777;
>     X[1] = 220610;
>     Y[1]= 2343627;
>     X[2] = 220818;
>     Y[2]= 2343477;
>     X[3] = 221109;
>     Y[3]= 2343777;
>     X[4] = 230504;
>     Y[4]= 2343627;
>     X[5] = 221102;
>     Y[5]= 2343477;
>     X[6] = X[0];
>     Y[6] = Y[0];
>
>
>     //I know the number of vertex is 7, six of my polygon and an extra
>     //vertex to close the polygon.
>
>     vertexcount = 7;
>
>     //I can't understand what is exactly the panParts variable. :(
>
>     panParts[0] = 1;
>     //What is nParts? For me my polygon has 1 part, an entire part. It is
> true?
>     nParts = 1;
>     //I give a shape id for this unique object.
>     ShapeId=1;
>
> //From the shp_api I took this line of code to create a feature/object
> //SHPCreateObject( nSHPType, iShape, nParts, panPartStart, panPartType,int
> nVertices, *padfX, * padfY, *padfZ, *padfM );
> //I have the nShapeType;
> //I give the ShapeId
> //I give the nParts
> //I don't know what is panParts
> //panPartType is NULL because it isn't a multipatch file
> //I know the numer of vertex
> //I now the number of vertex I have two arrays of coordinates.
> //padfZ and padfM are NULL, zero.
>
>     psObject = SHPCreateObject(nShapeType, ShapeId, nParts, panParts,
> NULL,
> vertexcount, X, Y, NULL, NULL );
>
>     SHPWriteObject( hSHP, -1, psObject );
>
>     SHPDestroyObject( psObject );
>
>     DBFClose( hDBF );
>
>     SHPClose( hSHP );
>
>
>     return 0;
> }
>
> [/CODE]
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>
> ------------------------------
>
> Message: 2
> Date: Mon, 18 Feb 2008 00:34:51 +0100
> From: Tom Kazimiers <2voodoo at gmx.de>
> Subject: Re: [Shapelib] Adding a polygon to a shapefile
> To: Shapelib Development <shapelib at lists.maptools.org>
> Message-ID: <47B8C49B.3080801 at gmx.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Joaquin,
>
> as fas as I understood you can not make this call:
> psObject = SHPCreateObject(nShapeType, ShapeId, nParts, panParts, NULL,
> vertexcount, X, Y, NULL, NULL );
>
> have you checked if osObject is null afterwards? Please try it.
> Could it be that the first and the last vertex of a polygon need to be
> the same? In your code they are different.
> For my writing I use: SHPCreateSimpleObject which implys some NULLs of
> yours - maybe you could try this, too.
>
> bye,
> Tom
>
>
> Joaquin Perez Valera schrieb:
> > Hi
> >
> > I can create shapefiles and they are valid when I work with
> > ArcCatalog. But the shapefiles are empty.
> >
> > Now I'm trying to add objects to my shapefile. I want to add polygons.
> >
> > First I create a shapefile and a dbf file with an a simple column.
> > Then it becomes valid for ArcCatalog.
> > Then I create 2 arrays of 7 elements X[7] and Y[7], and give a valor
> > to each element. Seven elements because
> > I want to draw a polygon of six vertices.
> >
> > After it I use psObject = SHPCreateObject to create my polygon and
> > after   SHPWriteObject( hSHP, -1, psObject ); to write it
> > in my shapefile.
> >
> > It's obviously that I'm doing something wrong.
> > But I don't know what.
> >
> > Can somebody help me or say me what I'm doing wrong?
> >
> > Thanks.
> >
> >
> > [CODE]
> > #include <iostream>
> > #include <cstdlib>
> > #include "shapefil.h"
> > #include "string.h"
> >
> >
> > using namespace std;
> > int main()
> >
> > {
> >     SHPHandle    hSHP;
> >     DBFHandle    hDBF;
> >     int        nShapeType,   nWidth = 3, vertexcount, *panParts,
> > ShapeId, nParts;
> >
> >     string  shape_name, Col1;
> >     Col1= "Column";
> >
> >     SHPObject    *psObject;
> >
> >
> >     cout << "Name of the new Shapefile" << endl;
> >     getline(cin,shape_name);
> >
> >     cout << "The shapefile is: " << shape_name << endl;
> >
> >     //Here I define the type of shapefile, the 5 is for a polygon.
> >     nShapeType=5;
> >
> >
> >     hSHP = SHPCreate( shape_name.c_str(), nShapeType );
> >
> >     hDBF = DBFCreate( shape_name.c_str() );
> >
> >
> >     cout <<"The shape has "<< DBFGetFieldCount( hDBF ) <<" columns" <<
> > endl;
> >
> >
> >
> >     DBFAddField( hDBF, Col1.c_str(), FTInteger,   nWidth, 0 );
> >     cout <<"Now the shape has " << DBFGetFieldCount( hDBF ) << "
> columns";
> >
> >     //At this point the shape is valid for ArcView
> >
> >     //Here I define an array of seven elements and I'll give a
> > coordinate for each element
> >
> >     double X[7], Y[7];
> >     X[0] = 220764;
> >     Y[0]= 2343777;
> >     X[1] = 220610;
> >     Y[1]= 2343627;
> >     X[2] = 220818;
> >     Y[2]= 2343477;
> >     X[3] = 221109;
> >     Y[3]= 2343777;
> >     X[4] = 230504;
> >     Y[4]= 2343627;
> >     X[5] = 221102;
> >     Y[5]= 2343477;
> >     X[6] = X[0];
> >     Y[6] = Y[0];
> >
> >
> >     //I know the number of vertex is 7, six of my polygon and an extra
> >     //vertex to close the polygon.
> >
> >     vertexcount = 7;
> >
> >     //I can't understand what is exactly the panParts variable. :(
> >
> >     panParts[0] = 1;
> >     //What is nParts? For me my polygon has 1 part, an entire part. It
> > is true?
> >     nParts = 1;
> >     //I give a shape id for this unique object.
> >     ShapeId=1;
> >
> > //From the shp_api I took this line of code to create a feature/object
> > //SHPCreateObject( nSHPType, iShape, nParts, panPartStart,
> > panPartType,int nVertices, *padfX, * padfY, *padfZ, *padfM );
> > //I have the nShapeType;
> > //I give the ShapeId
> > //I give the nParts
> > //I don't know what is panParts
> > //panPartType is NULL because it isn't a multipatch file
> > //I know the numer of vertex
> > //I now the number of vertex I have two arrays of coordinates.
> > //padfZ and padfM are NULL, zero.
> >
> >     psObject = SHPCreateObject(nShapeType, ShapeId, nParts, panParts,
> > NULL, vertexcount, X, Y, NULL, NULL );
> >
> >     SHPWriteObject( hSHP, -1, psObject );
> >
> >     SHPDestroyObject( psObject );
> >
> >     DBFClose( hDBF );
> >
> >     SHPClose( hSHP );
> >
> >
> >     return 0;
> > }
> >
> > [/CODE]
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Shapelib mailing list
> > Shapelib at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/shapelib
> >
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 18 Feb 2008 00:43:00 +0100
> From: Tom Kazimiers <2voodoo at gmx.de>
> Subject: Re: [Shapelib] Adding a polygon to a shapefile
> To: Shapelib Development <shapelib at lists.maptools.org>
> Message-ID: <47B8C684.5040701 at gmx.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Joaquin,
>
> sorry - I missed that you actually do have first and last elements the
> same of your vertex arrays :)
> But could you please write down where the error appears and what kind of
> error it is?
>
> cheers,
> Tom
>
> Tom Kazimiers schrieb:
> > Hi Joaquin,
> >
> > as fas as I understood you can not make this call:
> > psObject = SHPCreateObject(nShapeType, ShapeId, nParts, panParts,
> > NULL, vertexcount, X, Y, NULL, NULL );
> >
> > have you checked if osObject is null afterwards? Please try it.
> > Could it be that the first and the last vertex of a polygon need to be
> > the same? In your code they are different.
> > For my writing I use: SHPCreateSimpleObject which implys some NULLs of
> > yours - maybe you could try this, too.
> >
> > bye,
> > Tom
> >
> >
> > Joaquin Perez Valera schrieb:
> >> Hi
> >>
> >> I can create shapefiles and they are valid when I work with
> >> ArcCatalog. But the shapefiles are empty.
> >>
> >> Now I'm trying to add objects to my shapefile. I want to add polygons.
> >>
> >> First I create a shapefile and a dbf file with an a simple column.
> >> Then it becomes valid for ArcCatalog.
> >> Then I create 2 arrays of 7 elements X[7] and Y[7], and give a valor
> >> to each element. Seven elements because
> >> I want to draw a polygon of six vertices.
> >>
> >> After it I use psObject = SHPCreateObject to create my polygon and
> >> after   SHPWriteObject( hSHP, -1, psObject ); to write it
> >> in my shapefile.
> >>
> >> It's obviously that I'm doing something wrong.
> >> But I don't know what.
> >>
> >> Can somebody help me or say me what I'm doing wrong?
> >>
> >> Thanks.
> >>
> >>
> >> [CODE]
> >> #include <iostream>
> >> #include <cstdlib>
> >> #include "shapefil.h"
> >> #include "string.h"
> >>
> >>
> >> using namespace std;
> >> int main()
> >>
> >> {
> >>     SHPHandle    hSHP;
> >>     DBFHandle    hDBF;
> >>     int        nShapeType,   nWidth = 3, vertexcount, *panParts,
> >> ShapeId, nParts;
> >>
> >>     string  shape_name, Col1;
> >>     Col1= "Column";
> >>       SHPObject    *psObject;
> >>          cout << "Name of the new Shapefile" << endl;
> >>     getline(cin,shape_name);
> >>
> >>     cout << "The shapefile is: " << shape_name << endl;
> >>
> >>     //Here I define the type of shapefile, the 5 is for a polygon.
> >>     nShapeType=5;
> >>           hSHP = SHPCreate( shape_name.c_str(), nShapeType );
> >>
> >>     hDBF = DBFCreate( shape_name.c_str() );
> >>                  cout <<"The shape has "<< DBFGetFieldCount( hDBF )
> >> <<" columns" << endl;
> >>            DBFAddField( hDBF, Col1.c_str(), FTInteger,   nWidth, 0 );
> >>     cout <<"Now the shape has " << DBFGetFieldCount( hDBF ) << "
> >> columns";
> >>        //At this point the shape is valid for ArcView
> >>
> >>     //Here I define an array of seven elements and I'll give a
> >> coordinate for each element
> >>        double X[7], Y[7];
> >>     X[0] = 220764;
> >>     Y[0]= 2343777;
> >>     X[1] = 220610;
> >>     Y[1]= 2343627;
> >>     X[2] = 220818;
> >>     Y[2]= 2343477;
> >>     X[3] = 221109;
> >>     Y[3]= 2343777;
> >>     X[4] = 230504;
> >>     Y[4]= 2343627;
> >>     X[5] = 221102;
> >>     Y[5]= 2343477;
> >>     X[6] = X[0];
> >>     Y[6] = Y[0];
> >>           //I know the number of vertex is 7, six of my polygon and
> >> an extra
> >>     //vertex to close the polygon.
> >>        vertexcount = 7;
> >>        //I can't understand what is exactly the panParts variable. :(
> >>        panParts[0] = 1;
> >>     //What is nParts? For me my polygon has 1 part, an entire part.
> >> It is true?
> >>     nParts = 1;
> >>     //I give a shape id for this unique object.
> >>     ShapeId=1;
> >>    //From the shp_api I took this line of code to create a
> >> feature/object
> >> //SHPCreateObject( nSHPType, iShape, nParts, panPartStart,
> >> panPartType,int nVertices, *padfX, * padfY, *padfZ, *padfM );
> >> //I have the nShapeType;
> >> //I give the ShapeId
> >> //I give the nParts
> >> //I don't know what is panParts
> >> //panPartType is NULL because it isn't a multipatch file
> >> //I know the numer of vertex
> >> //I now the number of vertex I have two arrays of coordinates.
> >> //padfZ and padfM are NULL, zero.
> >>
> >>     psObject = SHPCreateObject(nShapeType, ShapeId, nParts, panParts,
> >> NULL, vertexcount, X, Y, NULL, NULL );
> >>        SHPWriteObject( hSHP, -1, psObject );
> >>        SHPDestroyObject( psObject );
> >>        DBFClose( hDBF );
> >>       SHPClose( hSHP );
> >>               return 0;
> >> }
> >>
> >> [/CODE]
> >>
> >>
> ------------------------------------------------------------------------
> >>
> >> _______________________________________________
> >> Shapelib mailing list
> >> Shapelib at lists.maptools.org
> >> http://lists.maptools.org/mailman/listinfo/shapelib
> >>
> >
> > _______________________________________________
> > Shapelib mailing list
> > Shapelib at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/shapelib
> >
>
>
>
> ------------------------------
>
> _______________________________________________
> Shapelib mailing list
> Shapelib at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/shapelib
>
>
> End of Shapelib Digest, Vol 46, Issue 3
> ***************************************
>
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