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20

If you are designing a map you plan on overlaying over google maps or virtual earth and creating a tiling scheme then i think what you are looking for are the scales for each zoom level, use these: 20 : 1128.497220 19 : 2256.994440 18 : 4513.988880 17 : 9027.977761 16 : 18055.955520 15 : 36111.911040 14 : 72223.822090 13 : 144447.644200 12 : 288895.288400 ...


13

I saw this answer on the Openlayers mailing list a few days ago. You need to make sure you are providing a version, such as v=3.6: <script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false&v=3.6"></script> Then it should disappear. -- May 17, 2012 edit: I just saw that this problem has returned on the ...


12

There exists no map of the entire earth in which all (true, spherical) circles remain truly round. However, there are ways of mapping the earth in which almost all sufficiently small circles are round. These are based on conformal projections. By definition, the changes that a conformal projection makes to distances within small areas are of two types ...


10

Direct tile access is not allowed by Google (and this is what ArcBruTile is doing). Usually this will get your IP address banned for awhile but they could also come after you for violating their TOS. fwiw, Arc2Earth will be adding support for this functionality in the next build. Instead of needing a Google Maps Premium license, you can purchase access at ...


10

I guess your circles look something like this: (Source: Esri mapping center blog) You will want to use Web Mercator EPSG:900913 instead of WGS84 EPSG:4326 for perfect circles More on this topic and an example of how the circles look like in Mercator: Tissot's indicatrix helps illustrate map projection distortion To make openlayers use Mercator, you ...


9

To help you understand the maths (not a precise calculation, it's just for illustration): Google's web map tile has 256 pixels of width let's say your computer monitor has 100 pixels per inch (PPI). That means 256 pixels are roughly 6.5 cm of length. And that's 0.065 m. on zoom level 0, the whole 360 degrees of longitude are visible in a single tile. You ...


7

The Mercator projection has been around for a few hundred years. I don't know when the ellipsoidal version of the algorithm came into being (I don't have my reference books at my current location), but certainly the spherical version is quite old. Both versions certainly pre-date the use for web-based map imagery. By ellipsoidal / spherical, I mean that the ...


6

There is such a table in the documentation of the Virtal Earth Tile System from Microsoft. But as said by GuillaumeC the values depends on the latitude and on the screen resolution. The table gives values as measured at the Equator and at a screen resolution of 96 dpi. PS: Not sure of that, but the zoom levels by Microsoft might be shifted by 1 in ...


6

Yes. ArcBruTile - Tile Services in ArcGIS Desktop ArcBruTile display tiles from OpenStreetMap, Bing, Google, SpatialCloud and TMS/WMS-C Services in ArcGIS Desktop. Update: looks like references to Google have been removed from the ArcBruTile site, likely because, as commenters point out, what they're doing violates the Google Maps ToS.


6

You can restrict number of request/retrived features/etc per second/hour per ip. Annother approch would be converting it to harldy readable format (i.e. custom projection) or rasterizing vector data (as Google/MS does). You may also try to encrypt it, but I think, as cipy said, the best way is not to show it ;)


5

Keep the source off the Internet. Implement a proxy webpage and check the parameters/urls. Only allow certain parameters etc, if they don't match the proper ones reject. This could allow you to limit usage by IPs etc.. If your users login. You can add token handling. If you use ArcGIS Server here is esri's page with sample proxy code: ...


5

Google's tools do not provide any way to do this kind of thing built in. While you might be able to do this by routing to a sufficient number of locations and checking the time, another tool that you might be interested in is Graphserver. GraphServer is a multimodal trip planner, which can take data from OpenStreetMap and other data sources. Some of the ...


5

hallo first, in the post in stackoverflow the discussion is about getting a GPS point and say if it is a building or a road. AFAIK, GPS does not have that precision. I never expect a GPS point to be more precise than 10 meters. of course it often is a little better than that but it can also be much more wrong. In Routing GPS units the software often snap ...


5

ArcMap has a Geoprocessing Tool that Adds XY Coordinates as two new fields in the attribute table. If you're set up in a projected coordinate system, you'll need to first change over to the geographic system in order for the output of the tool to be in Lat Long. Alternatively you can open a new map, set the data-frame to WGS 84 (Right-click 'Layers' in the ...


5

Your question contains a number of sub-questions - this answer addresses solving the server side part of spell checking. A while back I've implemented a spelling corrector for addresses based on Peter Norvig's How to Write a Spelling Corrector. Instead of using books to build your training corpus, your dictionary will be based on words tokenized out of ...


5

Well most people say Osmand is best as Android. Lacking of further knowledge, I can't judge on your particular case. You need to know what features you want a app for endusers or for mappers? support for smartphone or tablet? online or (full offline)? routing with different profiles? POI search, address lookup? OpenSource / free / commercial app? With ...


4

The answer depends on how the question is interpreted. One interpretation is, "Given that a GPS point is known (or assumed) to lie either on a building or on a road, what are the odds that it lies on the road?" To find this, compute a grid representing a 2D Gaussian function whose standard deviation equals the expected error in the GPS position. Use a ...


4

Looks like a custom function (do view-source on it). You'll need jQuery to use it: $(function(){ // Loop through all the sets of before and after pics $(".beforeafter").each(function(){ // Set the container's size to the size of the image ...


4

Not sure if this is "legal" but i just made it go away with CSS. .olLayerGoogleCopyright {display:none;} UPDATE Apparently this violates the terms of use: By doing so, you violate the Terms of Use. Instead, you should use a more recent version of OpenLayers - this problem was fixed in 2.11. Are you using 2.11? Apparently it's no longer a ...


4

There are two possibilities. The more likely is that you have Chrome zooming the page in or out, which introduces the white lines. Do cmd-0 (or ctrl-0) and see if that fixes it. Otherwise, add that line to your CSS file, which might be site.css or whatever. Add it to the bottom, though it doesn't matter much. A live example would make this question easier ...


4

Drag Marker and Geocoder with Coordinates https://gmaps-samples-v3.googlecode.com/svn-history/r49/trunk/draggable-markers/draggable-markers.html Entire code: <html> <head> <meta name="viewport" content="initial-scale=1.0, user-scalable=no" /> <script type="text/javascript" ...


4

As far as I know there is no way to use Google Street View in QGIS. QGIS without Globe does not offer 3D capabilities. Globe is a work in progress and currently does not work on Windows according to Sourcepole (http://sourcepole.ch/the-state-of-qgis-globe).


4

For the points you gathered from google maps, you should use WGS1984: GCS_WGS_1984 Authority: Custom Angular Unit: Degree (0.0174532925199433) Prime Meridian: Greenwich (0.0) Datum: D_WGS_1984 Spheroid: WGS_1984 Semimajor Axis: 6378137.0 Semiminor Axis: 6356752.314245179 Inverse Flattening: 298.257223563


3

I asked an iPad whiz, and he said that one possible way is to e-mail yourself the kmz file, have your e-mail client open it, and hope that iOS knows to open Google Earth in opening the attachment. He says that iPad has no "desktop" per se, so it doesn't work as one might expect a Mac or PC to work...


3

This can be done by creating a Network Link KML, with the <refreshInterval> and <viewRefreshMode> (reference) settings set appropriately. As listed in the example, you'll need a script which returns the new response, in this case by sending the query down to PostGIS to respond with an updated asKml result.


3

For Google Maps or any Web Accessible Mapping platform is a good idea to hold your data on your own server and use php (or asp - et al) to control whom has access. This a good method for doing this in Google Maps API - using a MySQL Database and PHP http://code.google.com/apis/maps/articles/phpsqlsearch.html#outputxml *First, you should put your database ...


3

I haven't got a full answer but an important point is the context of the building and the road. GPS accuracy falls dramatically in a very built up area because the radio signals are obscured by and bounce off buildings. So GPS readings in the country by a low building will be far more accurate than in a skyscaper 'canyon' as you get in major cities.


3

1 - I don't know well the Gmap API but I don't think you can't vectorize data. 2 - Regarding statistic tool, it could be worth to use a JS stat library like Jstat before sending data to google. You can eventually use a server side library. Depending on your needs and the language you're using you will find something. A global answer would be you need more ...


3

Well, obviously you'll have problem as long as you use basemap in EPSG:4326 projection. What you need is Spherical Mercator projection which, as you noticed, Google Maps and other commercial map providers are. Go ahead and read this to get a better grasp on this problem. For you offline mobile solution OpenStreetMap would probably be a good solution.


3

You can access a Gmap layer with openlayers through mapObject. See that example (and source code), which gives the ability to use gmap style. You can try to access events through mapObject. Never tested. By the way, the example I pointed out uses the version 3 of gmaps.



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