[Gvsig_english] Importing a raster image with gvSIG Mobile
Marcel Schoolmeesters
schoolmeesters at gmx.de
Fri Apr 1 14:56:16 CEST 2011
Hello,
google coordinates are EPSG:3785, I think? (old name: EPSG:900913) -
That was the easiest way to get coordinates. I have used the map for
u-center (from u-blox), because of using that application for testing
last year. So I easily could lookup zthe upper edge. I did not have any
Desktop GIS installed, perhaps I should do that ;) but I will need a map
of the region with identical points, don't I? or is it possibvle to
transform by click and enter coordinates?
Concerning your new map image: Did you change/rescale the image? it is
not the same anymore, so the new worldfile cannot be compared.
As mentioned before, the image is not in EPSG:4326 obviously, otherwise
it would not have to be resized by gvSIG Mobile ;) and the ratio is not
really small, I think...it is rather 0.5 in height or something surround it?
Regards,
Marcel
Am 01.04.2011 09:22, schrieb Juan Lucas Dominguez Rubio:
> Hello, I have realized that in your JGW file the first and fourth
> parameters dont have the same absolute value:
> 1.073E-05
> 0
> 0
> -6.352E-06
> 9.125678
> 53.490805
> This is not wrong, but maybe the application is not dealing well with it.
> To create ECW images, I have used FWTools http://fwtools.maptools.org
> - install
> - Start the command-line terminal from the new icon
> - move to the folder where the files are (cd ...)
> - type something like:
> gdal_translate -of ecw jpg-map.jpg ecw-map.ecw
> (JPG and JGW files in the current folder)
> I have recreated the JPG and JGW to have the same absolute value in
> the first and fourth parameters:
> https://correo.prodevelop.es/descarga/gvsig/mobile/new_map.zip
> Try that one and see if the image is ok now.
> More info:
> http://www.gdal.org/gdal_utilities.html
> http://www.gdal.org/ogr_utilities.html
> ************
> Apart from that, this is another consideration not related to the
> previous problem:
> How did you create that image? Your original JPG seems to be using a
> projected SRS (like Google's EPSG:900913 or the German EPSG:3146X).
> Did you simply compute the coordinates in EPSG:4326 of the corners and
> wrote the JGW file by hand? That would not be correct because there is
> not a linear relation between those SRS (in other words, the "rule of
> three" does not work with them). In this case, the error would be not
> visible because it's a small area (so actually that would be a simple,
> valid approximation), but it's always better to do a proper
> reprojection with gvSIG or FWTools, for example.
> Regards,
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
> ------------------------------------------------------------------------
> *De:* gvsig_internacional-bounces at listserv.gva.es en nombre de Marcel
> Schoolmeesters
> *Enviado el:* jue 31/03/2011 20:36
> *Para:* Users and Developers mailing list
> *Asunto:* Re: [Gvsig_english] Importing a raster image with gvSIG Mobile
>
> Hello,
>
>
> well, I have created the image for myself with google coordinates :-)
> and I've checked the coordinates of the image and of the cursor...of
> course....so definitely, it is the image, which is not scaled
> correctly each time, you can see when looking at those screenshots.
> The image must be compressed in height (using EPSG:4326) because of
> the location at 53° N...
>
> I've checked the ECW and it looks and works fine,....can you tell me
> the commands to create an ecw-file from worldfile? it is a commandline
> tool, right?
>
> And of course, you mention the "lot of things" the application is
> doing while zoom or pan....but the image is even not compressed in
> height being shown the first time (without any zoom)
>
> Well, I think that should be checked...if yomebody got time...it is
> not important to me at the moment...it might be nice to show some
> bugs, too :-) but don't know if it is planned to change in gvsig
> mobile 1.0?
>
>
> Regards
> Marcel
>
>
>
>
> Am 31.03.2011 19:10, schrieb Juan Lucas Dominguez Rubio:
>
> Hello,thanks for the files.
> I mean that when you do zoom and pan in gvSIG Mobile, the
> application does a lot of little things in order to draw the image
> using as little memory as possible, and if one of those steps is
> wrong, then the image might be misplaced, but I have never noticed
> this.
> I remember that there is a little bug that causes the GPS arrow to
> be misplaced when you do some zoom and pan: until the next GPS
> coordinates arrive (and refreshes the GPS arrow), it can be
> misplaced. Maybe that's the problem you noticed? Is the arrow
> misplaced even after you have received several new GPS coordinates?
> To find out who is misplaced (the image or the arrow) you can load
> a shapefile (which always is ok, I think).You can download some
> ECW and SHP of Bremenvorde from here:
> https://correo.prodevelop.es/descarga/gvsig/mobile/
> The files called "...31467..." are in EPSG:31467, in case you
> prefer those. I created them with GDAL and OGR, so I think they
> have a little error of 1 or 2 meters (which I think is not a
> problem in this case).
> So if you load the JPG, then the SHP and use the GPS, what happens?
> If the SHP and the JPG are consistent and the GPS is
> misplaced, then there is a bug related to the GPS
> arrow (temporarily? always?)
> If the GPS and the SHP are consistent and the JPG is not, then
> there is a problem with the WKR driver.
> Regards,
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
> ------------------------------------------------------------------------
> *De:* gvsig_internacional-bounces at listserv.gva.es en nombre de
> Marcel Schoolmeesters
> *Enviado el:* jue 31/03/2011 17:54
> *Para:* Users and Developers mailing list
> *Asunto:* Re: [Gvsig_english] Importing a raster image with gvSIG
> Mobile
>
> Hello.
>
> I know those performance problems. But _*if*_ the transformation
> is performed, it should _not_ be wrong I think :) better would be
> an error message which tells the user that the image is too big or
> something...
>
>
> I cannot upload the image (25MB *.png or 5MB *.jpg), but I have
> uploaded the jpg to rapidshare, instead. /(The png file is about
> 2MB too big, it won't even be loaded, so I did not upload it)/
>
> JPG: http://rapidshare.com/files/455277713/jpg-raster.zip
> ECW: http://rapidshare.com/files/455279357/ecw-map.ecw
>
>
> I have compressed the file to ecw, too, but it is not
> geo-referenced, I think. I tried AU ECW Compressor...because the
> manual says, it will add geo-information...but it doesn't....not
> from an extra worldfile.
>
> Well, to load the worldfile of the JPG, you need to change the
> getWorldFileExtensions() in WKFRasterDriver.java, I think. Or
> change the extension to *.wld... but I'm sure, you know. (however,
> jgw seems to be the default one, isn't it?)
>
>
> Regards,
>
> Marcel
>
>
>
>
> Am 31.03.2011 17:04, schrieb Juan Lucas Dominguez Rubio:
>
> Hello,
> When zooming in and out with a non-ECW image, the app performs
> some shift and clip operations to minimize the amount of
> memory needed. I have never seen any strange bevavior there,
> but there might be a bug, yes.
> gdal_translate (FWTools) is free and creates faster, more
> reliable ECW images.
> which format are you using?
> can you send the image to the list? (with the georef. file if
> it's not a ecw file)
> Regards,
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
> ------------------------------------------------------------------------
> *De:* gvsig_internacional-bounces at listserv.gva.es en nombre de
> Marcel Schoolmeesters
> *Enviado el:* jue 31/03/2011 16:51
> *Para:* Users and Developers mailing list
> *Asunto:* Re: [Gvsig_english] Importing a raster image with
> gvSIG Mobile
>
> Hey all,
>
> I've got new interesting findings :-)
>
> * The error of the height of the image does_not appear at
> all_ when I zoom *three *times.
> * When I zoom *twice*, the error appears_only in the
> middle _of the image, but not when I see the background
> of the Map! I cannot say exactly,...
> * But when I does not zoom or/*only once...or four times
> or more*/... the image is_not resized _I think...it is
> the original ratio....
>
> I have got some screenshots, so that you might understand it
> better :)
>
> Perhaps, it is a graphical bug? I don't know...perhaps,
> somebody's got an idea? would be cool to be fixed!
>
>
> Regards,
>
> Marcel
>
>
> Am 30.03.2011 16:42, schrieb Marcel Schoolmeesters:
>
> Thanks for the explanation.
>
> As I said, the ImageExt values are correct...(y is
> calculated by _y + _h, I think) .....I have debugged the
> data flow and everything is understandable up to this
> function (and afterwards. What the function is doing might
> be clear, and even the values of the viewRect,
> too,...after your little explanation, what should be
> self-evident :-)
>
> However, the final lower/left edge of the picture is not
> shown at 53.475096504° where it should be, but somewhere
> at 53.464...and I cannot find the code where this is
> calculated...(but better to say that I have given up
> because of so many steps...)
>
> Best regards,
>
> Marcel
>
>
> Am 30.03.2011 09:32, schrieb Juan Lucas Dominguez Rubio:
>
> Hello,
> that method computes the extent of the view when you
> add the first layer. The app knows the size of the
> screen and the extent of the layer, and their ratios
> are different, so you have to do a simple computation
> to find out the extent of the new view.
> Maybe you have misunderstood the extent of a layer and
> the extent of the view?
> When you add the first layer, the extent of the view
> is the smallest rectangle which contains the extent of
> the layer and, at the same time, respects the
> width/height ratio of the screen, of course.
> Regards,
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
> ------------------------------------------------------------------------
> *De:* gvsig_internacional-bounces at listserv.gva.es en
> nombre de Marcel Schoolmeesters
> *Enviado el:* mar 29/03/2011 21:20
> *Para:* Users and Developers mailing list
> *Asunto:* Re: [Gvsig_english] Importing a raster image
> with gvSIG Mobile
>
> well, I think the main problem of understanding is in
> function
> MapContext.*getExtentFromFullExtentAndImageSize*() ...
> I think the new height etc are calculated there?
>
> Am 29.03.2011 21:00, schrieb Marcel Schoolmeesters:
>
> Hello,
>
> I have tried to load a raster image (had to try
> jpg, because *.png did not even load), but I am
> getting a wrong position of the extent. Anybody
> got the same error?
>
> I have tried the debug mode, but there are too
> many functions to catch on. Perhaps anybody can help?
>
> Somewhere the map origin is changed from the upper
> edge to the lower edge, that far I could follow,
> but then the image extent (height) and the origin
> coords (of Y) has been changed. Why? it seems to
> be very hard to understand the whole way of
> building the image at the right place.
>
> However, in attachment the original rectangle and
> the changed one are shown with their values while
> debugging...
>
> The lower edge of the final image is positioned
> between those Y values (@ 53.464) but it needs to
> be positioned at 53.475....
>
> what is getRasterTansformation() actually doing?
>
>
> Thanks in advance, if anybody can help. However,
> that issue should be fixed, I think. The import of
> PNG is not even possible, as I mentioned before..
>
> Regards
>
> Marcel
>
>
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