From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 96E6F13838B for ; Tue, 30 Sep 2014 17:43:32 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 4E06EE0AFB; Tue, 30 Sep 2014 17:43:24 +0000 (UTC) Received: from lyseo.edu.ouka.fi (unknown [82.128.138.2]) by pigeon.gentoo.org (Postfix) with ESMTP id 13A28E0920 for ; Tue, 30 Sep 2014 17:43:22 +0000 (UTC) Received: from [100.66.19.213] (85-76-16-2-nat.elisa-mobile.fi [85.76.16.2]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by lyseo.edu.ouka.fi (Postfix) with ESMTPSA id A9AA0193F984 for ; Tue, 30 Sep 2014 20:43:21 +0300 (EEST) Subject: Re: [gentoo-user] "Headless question": Harvesting the results...software needed. References: <20140930140513.GJ3828@solfire> <542ABA4F.9060302@alectenharmsel.com> From: Matti Nykyri Content-Type: text/plain; charset=us-ascii X-Mailer: iPhone Mail (11D201) In-Reply-To: <542ABA4F.9060302@alectenharmsel.com> Message-Id: <3F710173-62E5-4000-8634-589BF3F8BBCE@iki.fi> Date: Tue, 30 Sep 2014 20:43:20 +0300 To: "gentoo-user@lists.gentoo.org" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 (1.0) X-Archives-Salt: c2fed937-4e8d-4cb3-976b-0a4031639a64 X-Archives-Hash: 966fae5a25da637d449c9927d985c85f > On Sep 30, 2014, at 17:12, Alec Ten Harmsel wrot= e: >=20 >=20 >> On 09/30/2014 10:05 AM, meino.cramer@gmx.de wrote: >> Suppose the GPS would already be attached >> to the board and works... >>=20 >> Is there any free available software and data for >> strict offline useage (which does NOT calls >> to home), which is able to map GPS data to a street/land >> map? >> I need both: The maps themselves and the logic to read >> GPS coordinates and map movements and ways to those maps. >>=20 >> Is something like that available for free or should >> I directly ask the NSA/CIA/FBI/...? >>=20 >> Thank you very much in advance for any help! >> Best regards, >> mcc > The only project I know of that has openly available map data is > OpenStreetMap (openstreetmap.org). I know they have an API, and they > probably (not sure) have maps available for download. >=20 > afaik the only way to combine various map data out of the box is to use > a GIS package like QGIS. You can write software to do this using the > proj4 library for an embedded box, not sure if anything for your > specific use case already exists and is open source. >=20 > Alec Sorry iphone send mail even if you don't wanna :/ What you are considering doing is quite a challenge. What kind of coordinate= s does your gps module give you? The gps system works with cartesian x y z c= oordinates. Then these are usually displayed to the user in WGS-84. This is a= quite hard mathematical problem (differential elliptical problem). Usually i= s done by your gps receiver and is approximated. GIS libraries have these fu= nctions built inside. Distances are easier and faster to calculate in cartes= ian coordinates. You need to calculate distance because coordinates from gps= will never coincide with any address. Open street maps provides a very good start, but addresses have great differ= ences in different countries. For example google misses addresses quite much= depending on where you are searching. Getting the address right requires go= od locality from the program. Addresses and roads are vector maps. The faste= st way to get address is to have the vector map of the world and then calcul= ate distance to the closest address. The database will be huge :) Maps are usually raster pictures which have some projection. When you displa= y them you can use 3d or 2d visual. In 3d (like google earth) you draw a sph= ere (or oblate spheroid) and draw textures on top of is to the right coordin= ates. In 3d everything needs to be converted to cartesian coordinates. Or in= 2d you decide a projection and then convert the projection of your maps to t= his projection. After that it is just easy drawing. GIS libraries contain al= l the needed tools for these operations. There are a few of them with open s= ource license. I have been doing some work with opengl 3d drawing maps. Good luck your proj= ect is quite big but it is sure very much fun :) --=20 -Matti