GIS and Web Tricks

QGIS gets Compass support

marco — Tue, 31 Jan 2012 23:52:30 +0000

After implementing GPS support for QGIS on Android I’ve implemented a plugin that reads the internal compass readings and shows the value in a small dock widget.
All theese new features are available in the master-alpha4 version and the nightly.
Hope you enjoy

QGIS on Android gets GPS support

marco — Mon, 30 Jan 2012 23:51:34 +0000

Lately I’ve been working on adding native GPS support to QGIS on Android, here is a short video showing how it works. A big thanks goes to the municipality of Schoten in Belgium which sponsored the developement. This functionality is included in the latest nightly builds as of yesterday.

GPS tracking on QGIS for android from Marco Bernasocchi on Vimeo.

QGIS on ANDROID talk at the Università degli Studi di Urbino

marco — Wed, 14 Dec 2011 10:17:01 +0000

Yesterday, thanks to Prof. Mauro De Donatis who invited me, I held a 2h talk at the Università degli Studi di Urbino about QGIS and QGIS on Android. The talk was attended by around 50 students and staff from Computer science, Geology and Ambient sciences.
I liked finally holding my first speech in Italian, although i felt more comfortable with English slides
Here you can find the slides. Thanks a lot to Tim Sutton Sutton for letting me use part of his QGIS for Humanity presentation
and here a little demo of the offline plugin at work:

QGIS Offline editing plugin on ANDROID from Marco Bernasocchi on Vimeo.

Creating non-versioned shared libraries for android

marco — Wed, 23 Nov 2011 13:17:48 +0000

While porting QGIS to android using necessitas I encountered the problem of versioned libs. Android does not support versioned libs and it is not going to. In the first vesions I used rpl -R -e libqgis_core.so.1.9.90 "libqgis_core.so\x00\x00\x00\x00\x00\x00\x00" $APK_LIBS_DIRand similar hacks to remove the version from the libs. But it was rather hacky. Then I found this post by Tom Russo where he mentioned how he changed his build process to force non versioned libs. I wrote him with some questions and finally, thanks to his hints, I managed to create a fairly general patch for libtool to make it generate android compatible configure scripts. I sent the patch to libtool and we’ll see what they think.diff --git a/m4/libtool.m4 b/m4/libtool.m4 index a9e20cf..a5cc8eb 100644 --- a/m4/libtool.m4 +++ b/m4/libtool.m4 @@ -2642,8 +2642,17 @@ linux* | k*bsd*-gnu | kopensolaris*-gnu) version_type=linux # correct to gnu/linux during the next big refactor need_lib_prefix=no need_version=no - library_names_spec='${libname}${release}${shared_ext}$versuffix ${libname}${release}${shared_ext}$major $libname${shared_ext}' - soname_spec='${libname}${release}${shared_ext}$major' + case $host_os in + # This must be Linux Android ELF which has no support for versioned libs. + linux-android*) + library_names_spec='$libname${shared_ext}' + soname_spec='${libname}${shared_ext}' + ;; + *) + library_names_spec='${libname}${release}${shared_ext}$versuffix ${libname}${release}${shared_ext}$major $libname${shared_ext}' + soname_spec='${libname}${release}${shared_ext}$major' + ;; + esac finish_cmds='PATH="\$PATH:/sbin" ldconfig -n $libdir' shlibpath_var=LD_LIBRARY_PATH shlibpath_overrides_runpath=no
Now, the problem is that this patch fixes libtool.m4 which is the file that is used when a project manager creates a configure script. So it will take time until libtool includes the patch, your project manager updates the configure script and so on. But, no problem, mean while you can just look for something similar in your configure file (I was very lucky using “this must be linux ELF” as search criteria) and replace it accordingly and reconfigure passing –host=arm-linux-androideabi (as you probably already do if you are reading this). I managed to crosscompile expat, gdal, geos, gsl, proj, libiconv and libcharset without version.
QGIS uses libpq (postgres client) to connect to some services, but there is no hint in the configure script about soname_spec and library_names_spec, so I searched for SO_VERSION and found it set in Makefile.shlib and adapted it accordingly. Bottom line is that you need to search creatively for anything related to soname, SO_VERSION and similar.

QGIS uses as well QWT, which is QMAKE based, in this case to generate non versioned libs it’s enough to add CONFIG += plugin to the .pro or .pri file.

Finally, in CMAKE you need IF (NOT ANDROID) SET_TARGET_PROPERTIES(qgis_core PROPERTIES VERSION ${COMPLETE_VERSION} SOVERSION ${COMPLETE_VERSION} ) ENDIF (NOT ANDROID)in your CMakeList.txt and call cmake with -DANDROID

Hope this helps and that more and more people port cool libs to android.
Ciao Marco

Sharing internet connection

marco — Sat, 01 Oct 2011 01:39:43 +0000

Today, for some bizarre reasons only my android phone was connecting to a WiFi. So I decided to use it as a tethered modem. The problem was that my friend Bruno could not use the net either, so since networkmanager ad-hoc networks were not working and it is our day off climbing we decided to keep our fingers trained on the keyboard.
Here are two little scripts to create an adhoc Wifi and forward internet connection over it.
enjoy Marco (and Bruno)
Server:
#!/bin/sh WIFINAME=bernaadhocwifi KEY=keyneedtobe13 #key needs to be 5, 13 or 29 chars GWIP=192.168.0.1 INTERFACE=wlan0 INTERFACETOSHARE=usb0 # #Uncomment get ip from android phone or anything you need #sudo ifconfig $INTERFACETOSHARE up #sudo dhclient $INTERFACETOSHARE #END CONFIG # sudo ifconfig $INTERFACE down sudo iwconfig $INTERFACE mode ad-hoc sudo iwconfig $INTERFACE essid $WIFINAME key s:$KEY sudo ifconfig $INTERFACE $GWIP netmask 255.255.255.0 up #Follow the above steps for another wireless card and set IP address in same subnet, say 192.168.0.2, and ping each other. # #Now to share the internet over wireless, sudo iptables -t nat -A POSTROUTING -o $INTERFACETOSHARE -j MASQUERADE #where usb0 is the connection you want to share #You also need to enable IP forwarding: sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward" #Or, to enable permanently add the following line to /etc/sysctl.conf #net.ipv4.ip_forward=1 #Some ISPs might limit the TTL so that you wont be able to share the internet. Fix: #sudo iptables -t mangle -A PREROUTING -j TTL --ttl-inc 1
Client
#!/bin/sh WIFINAME=bernaadhocwifi KEY=keyneedtobe13 #key needs to be 5, 13 or 29 chars IP=192.168.0.2 GWIP=192.168.0.1 INTERFACE=wlan0 #END CONFIG # #Using the shared internet (in Linux) sudo ifconfig $INTERFACE down sudo iwconfig $INTERFACE mode ad-hoc sudo iwconfig $INTERFACE essid $WIFINAME key s:$KEY sudo ifconfig $INTERFACE $IP netmask 255.255.255.0 up # #Now to use the shared internet on another computer, set it to ad-hoc mode and assign IP address in the same subnet as described above and perform the following: # #Set the IP of computer sharing internet as gateway sudo route add default gw $GWIP #Set DNS server. We're using Google's DNS. sudo sh -c "echo 'nameserver 8.8.8.8' >> /etc/resolv.conf"

GSoC 2011 final report

marco — Wed, 24 Aug 2011 01:06:22 +0000

So, it is over, after 3 months working on QGIS for android as a Google Summer of code project it is now time to wrap up what I did and didn’t do.

First of all a QGIS android app exists now and it has many features including:
- reading/writing projects
- raster support
- spatialite support
- wms support
- (apparent – untested) wfs and postgress support
- partial shape files support (string attributes still chrash the app)
- Fully functional gui (SymbologyV2 doesnt work yet)
- (all?) core C++ plugins beside globe (any takers?

Further more I created a series of build scripts that make it easier to set up a dev environement.

Unfortunately I didnt manage to implement live GPS tracking and a larger gui optimisation, but all in all I’m very happy with the results and seeing that few peoples are already testing it. Soon ill publish a video.

cheers
Marco

QGIS Android works!

marco — Sun, 21 Aug 2011 10:03:15 +0000

Just a quick screenshot to show that qgis on android is now a working reality. Tomorrow I’ll make a video and so on. The major missing thing now is reading shp files ad maybe spatialite… maybe tomorrow. Now it’s sunday
Ciao

test it now:

QGIS Android the first test map

marco — Sat, 20 Aug 2011 20:56:32 +0000

Today I loaded the first data into qgis and although the mapcanvas stays black, in the map composer the data is shown. Here some screenshots.

GSoC 2011 weekly report #12

marco — Sat, 20 Aug 2011 07:11:41 +0000

See my last posts. In short I managed to get qgis packaged as an apk and to properly run with only one major problem. The map canvas is always black. I ll investigate this till Tuesday.
Cheers

QGIS data providers and map canvas

marco — Fri, 19 Aug 2011 21:43:52 +0000

After finishing with the gui(see previous post) i started testing the data providers.reading and writing shp files always ends in an app crash. Loading rasters, wms and gpx seems to work but the mapcanvas is never drawn. I have to investigate why. But probably it has to do with the draw used in qgis. The properties are there and get updated, but the canvasstays black. The same happens with decorations plugins like north arrow and copyright.
Next things i want to check is the shape error and the canvas problem. Then probably sqlite and gps.
Ciao Marco