I wanted to ask you about the way to make spatial interpolation in google maps API. This means- I have values for some points inside an area and want to recalculate values for every point in this area (and create an raster overlay).
In "offline" GIS softwares, there are more methods to do this. For example Kriging (http://en.wikipedia.org/wiki/Kriging).
Thanks for answer
There is no real practical way to do such a thing. Spatial Interpolation is something you really need a full-blown GIS to accomplish. It requires storing, analyzing, and presenting data in way that ArcGis or QGis is best suited for. There is some new feature in ArcGis Online that works with Google Maps API but I don't know much about it and am unsure if it would be any help for you but a link is here.
I know, its not something geostatiscically correct, but I have made this:
- I have created a net of rectangle polygons.
- I have connected all my points to polygon they lie and have made mean value for polygons with at least one point
- I have checked every polygon without points and at least 2 neighbourly polygons with points, and have made mean from this neighbourly values
- I have checked again all my polygons with values and at least 2 neighbourly polygons with values and smoothed origin values according to the neighbours´ values.
Related
So, basic gist is, I have my own tiles of not the real world I'd like to display with the Google Maps viewer. I've found examples of how to split an existing single image into tiles for use with it, but nothing that deals with setting up your own tiler.
I have map data such as this:
https://dl.dropboxusercontent.com/u/44766482/superimage/index.html
Which right now is just a bunch of 1600x1600 images in an html table. This naive method works, but I'd like to switch to the more robust google api for better zooming and smarter streaming of the image data.
I've been unable to find a good example of how to generate your own tiles for the zoom levels and bring it together with some html/js.
If you want some more information for the goal process;
I have a python script that can output any size tiles of the map, at any zoom level. I'd like to bundle those together into a google maps api website. But in my own efforts I have not found a good example or documentation of how to do that. For one, I can only find examples of how the zoom levels work for the real world map, but not for a custom one.
Edit:
Got most things working as I want them, but I'm still confused regarding the "center" that can be set, as it's in lat and lng, which don't apply. I'd also like to set boundaries as currently it tries to load .png files outside of the maps range.
My current progress:
https://dl.dropboxusercontent.com/u/44766482/googlemapspreview/index.html
I think what you are looking for is the google maps imageMapTypes:
https://developers.google.com/maps/documentation/javascript/maptypes#ImageMapTypes
Basically, each zoom level is the 4 lower zoom tiles combined. A Projection function can be skipped to get orthogonal mapping.
I need a 'polygon' selector type functionality. Basically, the ability to drag lines to form multiple polygons; pref with the ability to edit the 'points' of the polygon after the shape has been 'closed' (but that's secondary) and/or move the polygons...
I generally dislike 'reinventing the wheel' and I figured I'd find tons of examples to work with, but I was wrong...
The polygon tool in Google Maps is just about perfect, but has anyone utilized it outside of GMaps? (I recall it required a GMap as an attribute from my work with Google Maps). Before I roll up my sleeves, I just want to ensure there isn't something already made (this is a very small part) - so if (a) Google Maps Polygon object is usable without a map, or (b) there's another library/project I'm missing please let me know.
Fabricjs is an option you can check.
Have a look at D3.js which has a great api for visualizing data and geo information. Besides the standard one-/two-dimensional brush there are plugins for more advanced types of brushes:
Polybrush. Providing a polygon brush.
lasso. Lassoing a selection by freely drawing a line path.
I am attempting to make a simple PhoneGap app that will allow a user to input lat/long points and bearings and calculate their estimated intersection, along with a measure of error. I would like to display the lines, intersection, and an error elipsoid on a map or at least a grid of latitude and longitude lines, so the user can visualize the accuracy of the point. The tricky part is that this will be used for wildlife tracking in areas where the user may not have cell service. Is there some sort of Javascript plugin that will make a lat/long grid available for me to draw georeferenced lines and shapes on? I would love to use something like the Google Maps API, but that clearly won't work for offline use. I've Googled quite a bit, but I'm not sure where to start with this or if it's even feasible at all.
This program is similar to what I'm trying to achieve: http://www.locateiii.com/
Any ideas are greatly appreciated.
I'd use d3.js and http://code.google.com/p/gmapcatcher/ something like this where you can keep the google maps offline. If that's not feasible you can always us D3 with a svg of the map.
I ended up using OpenLayers with OpenStreetMap tiles prepared by Maperitive. Simple and works well with PhoneGap.
I have an exercise in problem solving for those who like that kind of thing. I'm working on a mapping application that uses Google Maps. A user first enters a series of coordinates and a "radius". The user then requests either a line or an area be plotted. The plots are taking place on Google Maps using polygons. In other words, given the blue line (or area) defined by the blue points and a distance, calculate the red points and draw the red polygon where the edges are of the given distance away from the user-provided edges:
I have managed to get this to work in "most" situations by calculate forward and reverse bearings, then finding the points with a bearing 90 degrees off these in the appropriate direction. For the arcs I just calculated the location points along that arc at 5 degree intervals. In the case of the inside of an acute angle, I determine where the two lines intersect and use that point, but this fails miserably sometimes when the cross-track distance at that point is greater than the radius that was provided.
I'm hoping someone knows of an easier way? Maybe one that works all the time regardless of the ratio of the cross-track to radius distances? Or maybe a library already exists to do this?
I hope what I'm trying to do makes sense... It's hard to put in words. Maybe if I had the words a search would have been helpful even.
Well, the answer turned out to be simpler than I thought. It took me back to a lesson I was taught during CompSci 101 almost 15 years ago:
"Use existing libraries whenever possible."
Once I found out (via googling), that what I'm looking for isn't called an "offset" or a "scale" but is actually called a "buffer" in GIS computing, it was simple. There are some great libraries like Clipper by Angus Johnson that can do it, but I wanted something JavaScript specific.
That brought me to arcGIS's GeometryService. They even have a Google Maps version but it's only API v2. Luckily, there's an official, unsupported version I found via the arcGIS forums that works with GMaps API v3.
So, my solution was to use that, called arcgislink, and it's buffer function works perfectly with Google Maps LatLng points, Google Maps Polygons/Polylines, and any of the standard arcGIS types. Anyone else needing to do this with Google Maps, I highly recommend looking at their libraries.
In the general setting, this problem is quite difficult because it is a global one (you cannot just solve locally, at each polygon vertex but just handling the two incoming edges). And also uneasy because it involves circular arcs.
There is a solution which is quite unefficient but safe: assume you have a general polygon union algorithm (like http://gvu.gatech.edu/~jarek/graphics/papers/04PolygonBooleansMargalit.pdf); you will add inflated versions of every edge one by one (every time a rectangle and two half-disks approximated by polygons), together with the original polygon for closed shapes.
For the sake of efficiency, you can design a "sweepline" algorithm that works by slicing the plane with horizontal lines at every "event point", i.e. segment/arc endpoints and arc apexes, so that the configuration in every slice is simpler. Do you see what I mean ?
BTW, what do you call the "cross-track distance" ?
I need to show my clients what 'zone' they live in (how much they will pay depending on how far away they are from my business). I want to use Google Maps to give them a view of what roads/towns/cities/etc. are in what zone. I was going to make some kind of definable barrier of sorts that would emanate from the center point.
I would have it so one barrier line showed where it was x miles away from the center point, another barrier would define areas y miles away, another defining areas z miles away, and so on and so forth.
I've never used the Google API and I'm only slightly good at Javascript... What is the best path to take here to learning how to do this... or... even better... how would I do this?
Thanks for helping!
Cheers!
You can create polygons on the map and set the fill shading opacity such that it is slightly transparent. When you layer concentric circles over one another, you'll see the shading change slightly.
I wrote a series of posts on how to use the maps API for Google, Bing, and MapQuest that you might find useful.
http://www.onesadjam.com/search/label/mapping
Look at the documentation on google maps javascript api V3. I sense that you will be creating polygons - specifically look at how to do that. In the API, you can create a circle polygon, with options such as the center and radius, making your job very easy.