[GRASSLIST:548] Re: contribution to WIKI

[RAVI KUMAR]

Hi ,
  good to C a geologist on the list.
  GRASS is rather poor when it comes to Geo symbology. Like showing
  1. Dip and Strike of Bedding / Foliation
  2. Folds and plunge
  3. Lineation
  4. Faults/ Grabens.. and the list gos on.
   
  We will be too happy to use Ur code for representing lineaments (intensity?)
  ThanX in anticipation

"Carlos \"Guâno\" Grohmann" <carlos.grohmann at gmail.com> wrote:
  Hello all,

I have this little program in C that reads the output of v.out.ascii
and gives the azimuth and length of lines. I wrote the first version
in my MSc and it appear in Grohmann 2004, Computers & Geosciences.
After that I re-wrote the original (in pascal) in C, and recently made
some changes after suggestions from Ors Teglasy. I find it useful to
create rose diagrams of lineament maps, and I'd like to put it on the
WIKI site, but I'm not sure where should I put it (is there a section
for this kind of thing?), so I'd like to hear from you guys.

Carlos


--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________
"Good morning, doctors. I have taken the liberty of removing Windows
95 from my hard drive."
--The winning entry in a "What were HAL's first words" contest judged
by 2001: A SPACE ODYSSEY creator Arthur C. Clarke
#include 
#include 
#include 
#include 

/* max vertex per line */
#define MAX_VERTEX 100
/* maxlines per file */
#define MAX_LINHAS 5000
/* PI */
/*#define PI 3.141592654*/

FILE *entrada, *saida;
char arquivo_in[30],arquivo_out[30];
char header_stuff[12],linha[2],layer[1],layer_cat[7],cat[10];
double utm_n[MAX_LINHAS][MAX_VERTEX],utm_e[MAX_LINHAS][MAX_VERTEX]; 
double dx,dy,azim,hyp,arc,m; 
int i,j,k,n_vertex[MAX_LINHAS],n_linhas,n_pontos; 


main()
{
system("clear"); /* clear screen */

/* legal notes...*/ 

printf("\n************** AZIMUTH 0.5 **************\n\n");
printf("AZIMUTH calculates azimuth and lengths of vector\n");
printf("lines from DIG_ASCII files exported from GRASS-GIS.\n\n");
printf("Carlos H. Grohmann. IGc-USP-Brasil. guano at usp.br\n");
printf("Code improvement after suggestions from\n");
printf("Örs Téglásy, Hungary. orsteglasy at yahoo.com\n");
printf("This program is licenced under GPL 2.0 or later.\n\n");

printf("Your vector file should be exported with v.out.ascii\n");
printf("using the 'standard' format\n");
printf("like this: v.out.ascii input=vector output=ascii format=standard\n");
printf("---------------------------------------------------------\n");
printf("WARNING: version < 6.0 DIG_ASCII files have different format!\n");
printf("Don't use them as input!\n");
printf("WARNING: using -o (old format) option will result in incorrect output!\n");
printf("---------------------------------------------------------\n\n");


/* open input file... */
printf("Input DIG-ASCII file: ");
scanf("%s",&arquivo_in);
if(!(entrada=fopen(arquivo_in,"r")))
{
printf("\nError opening file!\n");
exit(1);
}

/* open output file...*/
printf("\nOutput (Azimuth/Length) file: ");
scanf("%s",&arquivo_out);
if((saida=fopen(arquivo_out,"w"))==NULL)
{
printf("\nCan't open file!\n");
exit(1);
}

/* read dig-ascii file header */
while(!feof(entrada))
{
fscanf(entrada,"%s",&header_stuff);
if(strcmp(header_stuff,"VERTI:")==0) break;
}

/* start line and vertex counters */
j=0; /* line counter */
k=0; /* vertex counter */

while(!feof(entrada))
{ 
n_linhas=j;
fscanf(entrada,"%s",&linha);
fscanf(entrada,"%d",&n_vertex[j]);
fscanf(entrada,"%d\n",&layer);

/*put the vertex in arrays */
for(k=0;k {
fscanf(entrada,"%lf",&utm_e[j][k]);
fscanf(entrada,"%lf",&utm_n[j][k]);
}
fscanf(entrada,"%s",&layer_cat);
fscanf(entrada,"%s",&cat);
j++;

}

printf("\nProcessing...\n");

for (j=0;j {

/* if it is a N-S line */
if(utm_e[j][0]==utm_e[j][n_vertex[j]-1])
azim=0,
hyp=abs(utm_n[j][0]-utm_n[j][n_vertex[j]-1]);
else

/* if it is a E-W line */
if(utm_n[j][0]==utm_n[j][n_vertex[j]-1])
azim=90,
hyp=abs(utm_e[j][0]-utm_e[j][n_vertex[j]-1]);
else
/* if first point of line is to West of second point */
if(utm_e[j][0] {
printf("\n linha %d: x0 menor que x1 ", j+1),
m=(utm_n[j][n_vertex[j]-1]-utm_n[j][0])/(utm_e[j][n_vertex[j]-1]-utm_e[j][0]),
printf("m= %f ",m),
dx=abs(utm_e[j][0]-utm_e[j][n_vertex[j]-1]),
dy=abs(utm_n[j][0]-utm_n[j][n_vertex[j]-1]),
hyp=hypot(dx,dy),
arc=atan(dx/dy),
azim=(arc*180)/M_PI;
if(m<0) azim=180-azim;
printf("azim= %3.2f\n",azim);
}
else

/* if first point of line is to East of second point */
if(utm_e[j][0]>utm_e[j][n_vertex[j]-1])
{
printf("\n linha %d: x0 maior que x1 ", j+1),
m=(utm_n[j][0]-utm_n[j][n_vertex[j]-1])/(utm_e[j][0]-utm_e[j][n_vertex[j]-1]),
printf("m =%f ",m),
dx=abs(utm_e[j][0]-utm_e[j][n_vertex[j]-1]),
dy=abs(utm_n[j][0]-utm_n[j][n_vertex[j]-1]),
hyp=hypot(dx,dy),
arc=atan(dx/dy),
azim=(arc*180)/M_PI;
if(m<0) azim=360-azim; else azim=180+azim;
printf("azim= %3.2f\n",azim);
}



fprintf(saida,"%3.2f %7.3f\n",azim,hyp);

}

printf("\n*** Done ***\n");

fclose(entrada);
fclose(saida);

return 0;
}


		
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