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Search found 35 results on 2 pages for 'xmax'.

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• min max coordinate of cells , given cell length in c#

  - by Raj

  Please see attached picture to better understand my question i have a matrix of cells of [JXI] , cell is square in shape with length "a" my question is .. is there a way to use FOR loop to assign MIN,MAX coordinate to each cell taking origin (0,0) at one corner Thanks "freeimagehosting.net/uploads/3b09575180.jpg" i was trying following code but no success int a ; a = 1; for (int J=1; J<=5; J++) { for (int I = 1; I <= 5; I++) { double Xmin = ((I - 1)*a ); double Ymin = ((J - 1) * a); double Xmax = (I * a ); double Ymax = (J * a); } }

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• Image/"most resembling pixel" search optimization?

  - by SigTerm

  The situation: Let's say I have an image A, say, 512x512 pixels, and image B, 5x5 or 7x7 pixels. Both images are 24bit rgb, and B have 1bit alpha mask (so each pixel is either completely transparent or completely solid). I need to find within image A a pixel which (with its' neighbors) most closely resembles image B, OR the pixel that probably most closely resembles image B. Resemblance is calculated as "distance" which is sum of "distances" between non-transparent B's pixels and A's pixels divided by number of non-transparent B's pixels. Here is a sample SDL code for explanation: struct Pixel{ unsigned char b, g, r, a; }; void fillPixel(int x, int y, SDL_Surface* dst, SDL_Surface* src, int dstMaskX, int dstMaskY){ Pixel& dstPix = *((Pixel*)((char*)(dst->pixels) + sizeof(Pixel)*x + dst->pitch*y)); int xMin = x + texWidth - searchWidth; int xMax = xMin + searchWidth*2; int yMin = y + texHeight - searchHeight; int yMax = yMin + searchHeight*2; int numFilled = 0; for (int curY = yMin; curY < yMax; curY++) for (int curX = xMin; curX < xMax; curX++){ Pixel& cur = *((Pixel*)((char*)(dst->pixels) + sizeof(Pixel)*(curX & texMaskX) + dst->pitch*(curY & texMaskY))); if (cur.a != 0) numFilled++; } if (numFilled == 0){ int srcX = rand() % src->w; int srcY = rand() % src->h; dstPix = *((Pixel*)((char*)(src->pixels) + sizeof(Pixel)*srcX + src->pitch*srcY)); dstPix.a = 0xFF; return; } int storedSrcX = rand() % src->w; int storedSrcY = rand() % src->h; float lastDifference = 3.40282347e+37F; //unsigned char mask = for (int srcY = searchHeight; srcY < (src->h - searchHeight); srcY++) for (int srcX = searchWidth; srcX < (src->w - searchWidth); srcX++){ float curDifference = 0; int numPixels = 0; for (int tmpY = -searchHeight; tmpY < searchHeight; tmpY++) for(int tmpX = -searchWidth; tmpX < searchWidth; tmpX++){ Pixel& tmpSrc = *((Pixel*)((char*)(src->pixels) + sizeof(Pixel)*(srcX+tmpX) + src->pitch*(srcY+tmpY))); Pixel& tmpDst = *((Pixel*)((char*)(dst->pixels) + sizeof(Pixel)*((x + dst->w + tmpX) & dstMaskX) + dst->pitch*((y + dst->h + tmpY) & dstMaskY))); if (tmpDst.a){ numPixels++; int dr = tmpSrc.r - tmpDst.r; int dg = tmpSrc.g - tmpDst.g; int db = tmpSrc.g - tmpDst.g; curDifference += dr*dr + dg*dg + db*db; } } if (numPixels) curDifference /= (float)numPixels; if (curDifference < lastDifference){ lastDifference = curDifference; storedSrcX = srcX; storedSrcY = srcY; } } dstPix = *((Pixel*)((char*)(src->pixels) + sizeof(Pixel)*storedSrcX + src->pitch*storedSrcY)); dstPix.a = 0xFF; } This thing is supposed to be used for texture generation. Now, the question: The easiest way to do this is brute force search (which is used in example routine). But it is slow - even using GPU acceleration and dual core cpu won't make it much faster. It looks like I can't use modified binary search because of B's mask. So, how can I find desired pixel faster? Additional Info: It is allowed to use 2 cores, GPU acceleration, CUDA, and 1.5..2 gigabytes of RAM for the task. I would prefer to avoid some kind of lengthy preprocessing phase that will take 30 minutes to finish. Ideas?

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• Storing parameters from a graph and applying to other graphs

  - by Braden

  I would like to store the xmin and xmax parameters from one geom_histogram and apply them to a second geom_histogram. I am putting both graphs on the same page using grid.arrange and would like them to have the same x range, while allowing the first graph to establish the range based on its data. The second graph is produced from a subset of the first graphs data, so it will not have data that falls outside of the x-range established by the first. But I don't want the range to shrink to fit the second graph.

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• R software : How to extract values from rasterstack with xy coordinates?

  - by Eddie

  I have a rasterstack(5 raster layers) that actually is a time series raster. r <- raster(nrow=20, ncol=200) s <- stack( sapply(1:5, function(i) setValues(r, rnorm(ncell(r), i, 3) )) ) > s class : RasterStack dimensions : 20, 200, 4000, 5 (nrow, ncol, ncell, nlayers) resolution : 1.8, 9 (x, y) extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0 names : layer.1, layer.2, layer.3, layer.4, layer.5 min values : -9.012146, -9.165947, -9.707269, -7.829763, -5.332007 max values : 11.32811, 11.97328, 15.99459, 15.66769, 16.72236 My objective is to plot each pixel and explore their behavior over time. How could I extract each pixels together with their x,y coordinates and plot a time series curve?

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• Drawing to the canvas

  - by Mattl

  I'm writing an android application that draws directly to the canvas on the onDraw event of a View. I'm drawing something that involves drawing each pixel individually, for this I use something like: for (int x = 0; x < xMax; x++) { for (int y = 0; y < yMax; y++){ MyColour = CalculateMyPoint(x, y); canvas.drawPoint(x, y, MyColour); } } The problem here is that this takes a long time to paint as the CalculateMyPoint routine is quite an expensive method. Is there a more efficient way of painting to the canvas, for example should I draw to a bitmap and then paint the whole bitmap to the canvas on the onDraw event? Or maybe evaluate my colours and fill in an array that the onDraw method can use to paint the canvas? Users of my application will be able to change parameters that affect the drawing on the canvas. This is incredibly slow at the moment.

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• How to scan convert right edges and slopes less than one?

  - by Zachary

  I'm writing a program which will use scan conversion on triangles to fill in the pixels contained within the triangle. One thing that has me confused is how to determine the x increment for the right edge of the triangle, or for slopes less than or equal to one. Here is the code I have to handle left edges with a slope greater than one (obtained from Computer Graphics: Principles and Practice second edition): for(y=ymin;y<=ymax;y++) { edge.increment+=edge.numerator; if(edge.increment>edge.denominator) { edge.x++; edge.increment -= edge.denominator; } } The numerator is set from (xMax-xMin), and the denominator is set from (yMax-yMin)...which makes sense as it represents the slope of the line. As you move up the scan lines (represented by the y values). X is incremented by 1/(denomniator/numerator) ...which results in x having a whole part and a fractional part. If the fractional part is greater than one, then the x value has to be incremented by 1 (as shown in edge.incrementedge.denominator). This works fine for any left handed lines with a slope greater than one, but I'm having trouble generalizing it for any edge, and google-ing has proved fruitless. Does anyone know the algorithm for that?

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• plot 4 different plots inside 1 pdf

  - by ifreak

  I have 2 data frames which i want to generate 3 plots from them and place them inside 1 pdf file as a single column. i want all the plots to have the same x-axis limits(basically the same x-axis) even thought they differ in the name and how they were obtained. the dataframes looks something like that: d1 X Y Z 0.04939317 -0.4622222 13651 0.03202451 -0.4261000 13401 0.09950793 -0.3233025 13151 0.11548556 -0.4637981 12486 0.09817597 -0.4751886 12236 0.15770701 -0.5819355 11986 and d2 V0 V1 V2 V3 sign 1 1 0.379 0.612 pos 2 1 0.378 0.620 pos 3 1 0.578 0.571 neg 4 1 0.978 0.561 pos 5 1 0.758 0.261 neg 6 1 0.378 0.126 neg P.S : both data frames are bigger than this, this is only a part of them V0, V1 and Z range from 1 to 20000 the plots that i created are : From d2 d2plot=ggplot(d1, aes(V0,V1, fill=sign)) + geom_tile()+ scale_fill_manual(values = c("neg" = "yellow", "pos"="red")) +geom_vline(xintercept =10000 ) +geom_text(mapping=aes(x=10000,y=0, label="Stop"), size=4, angle=90, vjust=-0.4, hjust=0) From d1 d1plot = ggplot(d2) + geom_errorbarh(aes(x=z,xmin=z-50,xmax=z+50, y=Y, height = 0.02),color="red")+ opts(legend.position = "none") +geom_vline(xintercept = 10000) +geom_text(mapping=aes(x=10000,y=-0.3, label="Stop"), size=4, angle=90, vjust=-0.4, hjust=0) i've tried grid.arrange(d1plot,d2plot,ncol=1) but the x-axis is different for each plot, i tried changing the aspect ratio, but this will change the y-axis ..i've also tried to use facet_wrap but the problem that my x-axis values have different values, i just want the limits and breaks to be the same and the plots all be aligned in 1 column based on 1 x-axis to comapre the value of the statistical methods in an easy way.

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• Estimating the boundary of arbitrarily distributed data

  - by Dave

  I have two dimensional discrete spatial data. I would like to make an approximation of the spatial boundaries of this data so that I can produce a plot with another dataset on top of it. Ideally, this would be an ordered set of (x,y) points that matplotlib can plot with the plt.Polygon() patch. My initial attempt is very inelegant: I place a fine grid over the data, and where data is found in a cell, a square matplotlib patch is created of that cell. The resolution of the boundary thus depends on the sampling frequency of the grid. Here is an example, where the grey region are the cells containing data, black where no data exists. OK, problem solved - why am I still here? Well.... I'd like a more "elegant" solution, or at least one that is faster (ie. I don't want to get on with "real" work, I'd like to have some fun with this!). The best way I can think of is a ray-tracing approach - eg: from xmin to xmax, at y=ymin, check if data boundary crossed in intervals dx y=ymin+dy, do 1 do 1-2, but now sample in y An alternative is defining a centre, and sampling in r-theta space - ie radial spokes in dtheta increments. Both would produce a set of (x,y) points, but then how do I order/link neighbouring points them to create the boundary? A nearest neighbour approach is not appropriate as, for example (to borrow from Geography), an isthmus (think of Panama connecting N&S America) could then close off and isolate regions. This also might not deal very well with the holes seen in the data, which I would like to represent as a different plt.Polygon. The solution perhaps comes from solving an area maximisation problem. For a set of points defining the data limits, what is the maximum contiguous area contained within those points To form the enclosed area, what are the neighbouring points for the nth point? How will the holes be treated in this scheme - is this erring into topology now? Apologies, much of this is me thinking out loud. I'd be grateful for some hints, suggestions or solutions. I suspect this is an oft-studied problem with many solution techniques, but I'm looking for something simple to code and quick to run... I guess everyone is, really! Cheers, David

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• close file with fclose() but file still in use

  - by Marco

  Hi all, I've got a problem with deleting/overwriting a file using my program which is also being used(read) by my program. The problem seems to be that because of the fact my program is reading data from the file (output.txt) it puts the file in a 'in use' state which makes it impossible to delete or overwrite the file. I don't understand why the file stays 'in use' because I close the file after use with fclose(); this is my code: bool bBool = true while(bBool){ //Run myprogram.exe tot generate (a new) output.txt //Create file pointer and open file FILE* pInputFile = NULL; pInputFile = fopen("output.txt", "r"); // //then I do some reading using fscanf() // //And when I'm done reading I close the file using fclose() fclose(pInputFile); //The next step is deleting the output.txt if( remove( "output.txt" ) == -1 ){ //ERROR }else{ //Succesfull } } I use fclose() to close the file but the file remains in use by my program until my program is totally shut down. What is the solution to free the file so it can be deleted/overwrited? In reality my code isn't a loop without an end ; ) Thanks in advance! Marco Update Like ask a part of my code which also generates the file 'in use'. This is not a loop and this function is being called from the main(); Here is a piece of code: int iShapeNr = 0; void firstRun() { //Run program that generates output.txt runProgram(); //Open Shape data file FILE* pInputFile = NULL; int iNumber = 0; pInputFile = fopen("output.txt", "r"); //Put all orientations of al detected shapes in an array int iShapeNr = 0; int iRotationBuffer[1024];//1024 is maximum detectable shapes, can be changed in RoboRealm int iXMinBuffer[1024]; int iXMaxBuffer[1024]; int iYMinBuffer[1024]; int iYMaxBuffer[1024]; while(feof(pInputFile) == 0){ for(int i=0;i<9;i++){ fscanf(pInputFile, "%d", &iNumber); fscanf(pInputFile, ","); if(i == 1) { iRotationBuffer[iShapeNr] = iNumber; } if(i == 3){//xmin iXMinBuffer[iShapeNr] = iNumber; } if(i == 4){//xmax iXMaxBuffer[iShapeNr] = iNumber; } if(i == 5){//ymin iYMinBuffer[iShapeNr] = iNumber; } if(i == 6){//ymax iYMaxBuffer[iShapeNr] = iNumber; } } iShapeNr++; } fflush(pInputFile); fclose(pInputFile); } The while loop parses the file. The output.txt contains sets of 9 variables, the number of sets is unknown but always in sets of 9. output.txt could contain for example: 0,1,2,3,4,5,6,7,8,8,7,6,5,4,1,2,3,0

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• Running two wsgi applications on the same server gdal org exception with apache2/modwsgi

  - by monkut

  I'm trying to run two wsgi applications, one django and the other tilestache using the same server. The tilestache server accesses the db via django to query the db. In the process of serving tiles it performs a transform on the incoming bbox, and in this process hit's the following error. The transform works without error for the specific bbox polygon when run manually from the python shell: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/TileStache/__init__.py", line 325, in __call__ mimetype, content = requestHandler(self.config, environ['PATH_INFO'], environ['QUERY_STRING']) File "/usr/lib/python2.7/dist-packages/TileStache/__init__.py", line 231, in requestHandler mimetype, content = getTile(layer, coord, extension) File "/usr/lib/python2.7/dist-packages/TileStache/__init__.py", line 84, in getTile tile = layer.render(coord, format) File "/usr/lib/python2.7/dist-packages/TileStache/Core.py", line 295, in render tile = provider.renderArea(width, height, srs, xmin, ymin, xmax, ymax, coord.zoom) File "/var/www/tileserver/providers.py", line 59, in renderArea bbox.transform(METERS_SRID) File "/usr/local/lib/python2.7/dist-packages/django/contrib/gis/geos/geometry.py", line 520, in transform g = gdal.OGRGeometry(self.wkb, srid) File "/usr/local/lib/python2.7/dist-packages/django/contrib/gis/gdal/geometries.py", line 131, in __init__ self.__class__ = GEO_CLASSES[self.geom_type.num] File "/usr/local/lib/python2.7/dist-packages/django/contrib/gis/gdal/geometries.py", line 245, in geom_type return OGRGeomType(capi.get_geom_type(self.ptr)) File "/usr/local/lib/python2.7/dist-packages/django/contrib/gis/gdal/geomtype.py", line 43, in __init__ raise OGRException('Invalid OGR Integer Type: %d' % type_input) OGRException: Invalid OGR Integer Type: 1987180391 I think I've hit the non thread safe issue with GDAL, metioned on the django site. Is there a way I could configure this so that it would work? Apache Version: Apache/2.2.22 (Ubuntu) mod_wsgi/3.3 Python/2.7.3 configured Apache apache2/sites-available/default: <VirtualHost *:80> ServerAdmin ironman@localhost DocumentRoot /var/www/bin LogLevel warn WSGIDaemonProcess lbs processes=2 maximum-requests=500 threads=1 WSGIProcessGroup lbs WSGIScriptAlias / /var/www/bin/apache/django.wsgi Alias /static /var/www/lbs/static/ </VirtualHost> <VirtualHost *:8080> ServerAdmin ironman@localhost DocumentRoot /var/www/bin LogLevel warn WSGIDaemonProcess tilestache processes=1 maximum-requests=500 threads=1 WSGIProcessGroup tilestache WSGIScriptAlias / /var/www/bin/tileserver/tilestache.wsgi </VirtualHost> Django Version: 1.4 httpd.conf: Listen 8080 NameVirtualHost *:8080 UPDATE I've added the a test.wsgi script to determine if the GLOBAL interpreter setting is correct, as mentioned by graham and described here: http://code.google.com/p/modwsgi/wiki/CheckingYourInstallation#Sub_Interpreter_Being_Used It seems to show the expected result: [Tue Aug 14 10:32:01 2012] [notice] Apache/2.2.22 (Ubuntu) mod_wsgi/3.3 Python/2.7.3 configured -- resuming normal operations [Tue Aug 14 10:32:01 2012] [info] mod_wsgi (pid=29891): Attach interpreter ''. I've worked around the issue for now by changing the srs used in the db so that the transform is unnecessary in tilestache app. I don't understand why the transform() method, when called in the django app works, but then in the tilestache app fails. tilestache.wsgi #!/usr/bin/python import os import time import sys import TileStache current_dir = os.path.abspath(os.path.dirname(__file__)) project_dir = os.path.realpath(os.path.join(current_dir, "..", "..")) sys.path.append(project_dir) sys.path.append(current_dir) os.environ['DJANGO_SETTINGS_MODULE'] = 'bin.settings' sys.stdout = sys.stderr # wait for the apache django lbs server to start up, # --> in order to retrieve the tilestache cfg time.sleep(2) tilestache_config_url = "http://127.0.0.1/tilestache/config/" application = TileStache.WSGITileServer(tilestache_config_url) UPDATE 2 So it turned out I did need to use a projection other than the google (900913) one in the db. So my previous workaround failed. While I'd like to fix this issue, I decided to work around the issue this type by making a django view that performs the transform needed. So now tilestache requests the data through the django app and not internally.

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