I have a list of longitude and latitude points for various houses, offices, etc. I am trying to split them up to determine if they are inside a certain Way or not. I don't want to use the old "centre point" of an area and then radius value as that is not accurate enough.
So for example if I had 4 locations in an Way like "Richmond Upon Thames" that looks like this:
It should return just point B and C. Is this possible using Open Street Maps API?
If you like Java, you could load the way as a Polygon and use the JTS (Java Topology Suite) library, or the AWT library to compute whether your points are inside or not.
Here is an example of how the Atlas library uses a combination of both in that specific case. For you it would look like this:
Convert each latitude/longitude pair of the Way to a Location object
Add each Location to a List and create a new Polygon with it
Call the Polygon.fullyGeometricallyEncloses(Location) method on that Polygon with each of the points of interest you have
The Atlas library is available in Maven Central for you to download.
Related
Does anyone have suggestions regarding APIs available (free and paid) for posting a lat/long and the API returning a geoJSON shape file built from the lat/long posted?
For example, if I want to a shapefile of a 50 meter circle, derived from a lat/long 42.38567/-86.26877 CenterPoint, are there APIs that can do that? I have 24,000 locations I need this for, and I would very much like not to hand draw 24K polygons on a map.
I've investigated turf.js and developer.here.com but the documentation has been pretty unclear on what endpoint to post to, to solve this problem.
Most geographical libraries have buffer method, meaning they can do it locally (you don't even need any external API).
E.g. geopandas has buffer(distance, resolution) method - distance controls the radius, and resolution tells how precise the circle has to be. You construct point, call buffer method - get circle (approximated as polygon) as output.
Or you can load these points to a database with geospatial functionality (say, PostgreSQL + PostGIS) and call ST_Buffer method to do the same.
When searching on Zillow using an address, the URL looks like this:
http://www.zillow.com/homes/{Street}", -"{City}," -"{State}" "{PostalCode}_rb/
However, there seems to be no documentation regarding the use of geographic coordinates in such a url.
How to use latitude and longitude instead of an address?
An answer in Can I search Zillow using latitude and longitude coordinates? - Zillow Questions (the 1st Google result on "Zillow search by coordinates") dated 03.2015 gives an example:
http://www.zillow.com/homes/#/homes/for_sale/fsba,fsbo,new_lt/1_pnd/88.769211,-70.092773,-90,-158.686523_rect/3_zm/0_mmm/
Testing shows that only the http://www.zillow.com/homes and /88.769211,-70.092773,-90,-158.686523_rect parts are required.
It's x0,y0,x1,y1 (the direction between the points can be any). (The coordinates in the example are quite strange and specify an area up to the North Pole. More realistic ones are e.g. 53.67068,-71.323242,13.453737,-127.045898_rect.)
Since the last test, the technique stopped working. Moreover, coordinates appear to have vanished from property details as well!
There is no way provided to bring up a specific object by coordinates - they are instead uniquely identified by an ID (ZPID - Zillow Property ID) - and the way to bring up one as of now is e.g. http://www.zillow.com/homedetails/7044216_zpid/.
A possible reason is there's no way to guarantee that coordinates identify anything or identify something uniquely. I.e. coordinates are conceptually a search term rather than a means of identification.
Finally, do keep in mind that all this is undocumented and is subject to change (you can already see one quite-a-change above). They only support API as the means to access their services programmatically.
I am developing a location-based application in which I need to get nearby location name of any geopoint selected by user. I'm using Google Places API which is working fine for me.
Only problem is the service returns null for geopoints in water. Is there any way that I can retrieve nearby locations for a geopoint in water or ocean?
AFAIK the API has no way to do that.
So, you've got two options, in order of the effort it takes:
When user taps water just throw a dialog saying "Please select a
point on land". Next to no effort and will slightly annoy the user.
Try to find the closest land geopoint yourself and use it to run the API request on
(instead of the original point). Below are some ideas on that.
A good approach can be based on this answer: basically you can get a KML file with land polygons. For performance reasons, you can simplify the polygons to the extent that makes sense for your zoom levels. Now if your point is in one of those polygons -- it's sea. And you can simply iterate over all polygon edges and pick the one that's closest to your point, then pick a point on it - again closest to your point - and do one little epsilon-sized step towards the outside of the polygon to get a land point you can do a geocode request on. Also, the original author suggests you can use Haversine formula to determine neares land point -- I'm not really familiar with the appliance of that one.
The downside is, you have to deal with KML, iterate over a lot of polygons and optimize them (and lose precision doing that, in addition to possible differences between marineregions.org data and Google Places data)
Another cool trick you could try is using Sobel Filter [edge detection] on the visible map fragment to determine where coastline is (although you will get some false positives there), then trace it (as in raster->vector) to get some points and edges to calculate the closest land position with, in a manner similar to the former approach. Here's a clumsy drawing of the idea
For Sobel edge detection, consider GPUImage lib -- they have the filter implemented and it's probably going to work crazy fast since the lib does all the calculations on GPU.
UPD Turns out there's also a service called Koordinates that has coastline data available, check the answer here
I have the longitude and latitude and the name of the place I want to look for. How do I edit the Google Maps URL so that I obtain all the places (name of the places) near a set of coordinates?
I know I could do this using Google Map API, but just for a link seems a lot of trouble.
You can use the query parameter ll for your lat and long, and you can use the query parameter q for what you want to search.
http://maps.google.com/?ll=39.774769,-74.86084
Or you can
http://maps.google.com/?q=your+query
Yeah, I had the same question for a long time and I found the perfect one. Here are some parameters from it.
https://maps.google.com/?parameter=value
q=
Used to specify the search query in Google maps search.
eg :
https://maps.google.com/?q=newyork or
https://maps.google.com/?q=51.03841,-114.01679
near=
Used to specify the location instead of putting it into q. Also has
the added effect of allowing you to increase the AddressDetails
Accuracy value by being more precise. Mostly only useful if q is a
business or suchlike.
z=
Zoom level. Can be set 19 normally, but in certain cases can go up to 23.
ll=
Latitude and longitude of the map centre point. Must be in that order. Requires decimal format. Interestingly, you can use this without q, in which case it doesn’t show a marker.
sll=
Similar to ll, only this sets the lat/long of the centre point for a business search. Requires the same input criteria as ll.
t=
Sets the kind of map shown. Can be set to:
m – normal map
k – satellite
h – hybrid
p – terrain
saddr=
Sets the starting point for directions searches. You can also add text into this in brackets to bold it in the directions sidebar.
daddr=
Sets the end point for directions searches, and again will bold any text added in brackets.You can also add "+to:" which will set via points. These can be added multiple times.
via=
Allows you to insert via points in directions. Must be in CSV format. For example, via=1,5 addresses 1 and 5 will be via points without entries in the sidebar. The start point (which is set as 0), and 2, 3 and 4 will all show full addresses.
doflg=
Changes the units used to measure distance (will default to the standard unit in country of origin). Change to ptk for metric or ptm for imperial.
msa=
Does stuff with My Maps. Set to 0 show defined My Maps, b to turn the My Maps sidebar on, 1 to show the My Maps tab on its own, or 2 to go to the new My Map creator form.
reference : http://moz.com/ugc/everything-you-never-wanted-to-know-about-google-maps-parameters
additional info:
http://maps.google.com/maps?q=loc:
put in latitude and longitude after, example:
http://maps.google.com/maps?q=loc:51.03841,-114.01679
this will show pointer on map, but will suppress geocoding of the address, best for a location without an address, or for a location where google maps shows the incorrect address.
As of Jan 2018 (update: still works in May 2022) the latest URL is:
https://google.com/maps/search/*your search string* (address, landmark, city, etc. Spaces are ok)
Examples:
https://google.com/maps/search/empire state building
https://google.com/maps/search/1600 Pennsylvania Ave NW, Washington, DC 20500
You can use the new URL for Google Maps: https://www.google.com/maps/#39.774769,-74.86084,18z
equivalent to http://maps.google.com/?ll=39.774769,-74.86084.
39.774769 is the latitude and -74.86084 is longitude and 18z is 18 zoom level.
Google now has a documentation page dedicated to Maps URLs:
https://developers.google.com/maps/documentation/urls/guide
An API key is not required.
Manipulating one of the examples, I came up with this URL scheme that fits your question:
https://www.google.com/maps/search/<search term>/#<coordinates>,<zoom level>z
A valid example of this would be:
https://www.google.com/maps/search/pizza/#41.089988,-81.542901,12z
This should show you all of the pizza places around Akron, Ohio.
I'm working on a project that contains Thomas Brothers Map page and grid numbers. Is there a way to programatically convert from this map page to a latitude & longitude?
An Example would be for the intersection of the US101 & I405 freeways.
ThomasBrothers: 561-3G (page-grid)
Not that I know of, but I don't have a lot of experience with Thomas bros maps. Are you talking about printed version of the maps or is there a link somewhere to an online map?
If you just need a few lat/longs, then you can look up the locations that correspond to the grid and get the lats and longs manually at many websites, including http://itouchmap.com/latlong.html
If you provide a link to a Thomas bros map that you are using, I might be able to help further.
By looking at the link above, you can determine that US 101 and I-405 has a latitude of 34.16073390017978 and a longitude of -118.46952438354492.
Your best source would be the map publisher. If they choose to help, someone there can tell you exactly what you need to know. If they won't help you, it's unlikely that they've released the information to anyone else.
If that's the case, you could do some work by hand to correlate one point from the map grid to your target coordinate system. Effectively, you could reverse engineer a mapping "datum" for each page. You'd also have to know what map projection was used to render the maps, so that you can calculate the transform from the map coordinates to the geographic coordinates as you move away from your "origin". Finally, you'll need to establish the orientation of the map, since different notions of "north" exist.
It sounds like the Thomas maps use a new grid for every page, rather than bleeding the grid continuously from page to page. If that's the case, you'll have to correlate one point on each map. For example, find a spot where a map grid intersection coincides with a notable road intersection. Then you can find the coordinates of the road intersection using a map with latitude and longitude (a topographic map, TerraServer, etc.). Doing this with two points on the same vertical grid line should help you establish the north used on the map as well.
The short answer is that each of the nine regions has a grid derived from a Lambert conformal conic projection with custom parameters, so you cannot write a conversion program without the parameters.
I've also got ThomasBros. pages that I would like to convert to lat/long for lookup against Google Maps API. They also provided something called TBXY ... not sure what this is -- perhaps some notation for GPS/lat/long?
<Area>"El Cajon"</Area>
<ThomasBrothers>"1297 5E"</ThomasBrothers>
<TBXY>"6481390:1827008"</TBXY>
Thomas Brothers Maps invested a lot when developing their GIS system to create their digital mapping system. Though the first "digitally produced" map was Sacramento County-1990, the development began back in 1986. I expect that their map projection equations are a well guarded trade-secret, which Rand McNally now owns. I'd don't know those equations, but would also like to know them.
There are 9 projections covering the 48 states. If you know the equations for Los Angeles, it is valid across California & Nevada. Oregon & Washington have their own projection. Arizona, New Mexico, Colorado, and Utah share another projection.
I do know this...
As many know, the page grid is an exact 1/2 mile square, or 2640 feet by 2640 feet. The coordinate measurement unit is 1 foot.
To determine the Thomas Brothers XY Coordinate, get one or more of the Thomas Guide CD- ROM maps, which were recently discontinued. The last ones produced for certain California counties were the 2008 edition. Last editions for Seattle, Portland, Las Vegas, and Phoenix/Tucson were the 2007 edition. Each is still available on the Rand McNally website for $20.
When you geo-code a group of addresses, you'll see an output file with the TGXY coordinates and Lat/Lon for the addresses you specified, and the page # and grid that point is in. Once that file is open, you can click on the map to add additional geo-coded points, which will also provide both the coordinates. The output file is saved in an Access database ".mdb" file.
If you know a lot about map projections or solid geometry, the set of corresponding TGXY and Lat/Lon coordiantes will provide you some good data for testing.
As you mentioned San Diego Page 1297, I'll provide its bordering coordinates.
West x=3062760
East x=3086520
North y=0985040
South-y=0966560
This is not in range of the "TBXY" you found on Google. Maybe it's the same projection, with a relocated origin.