I'm a bit new with Google Maps API, so I don't know if the following question is well asked.
I'm trying to create a v3 powered custom map for a game world. I will use Google Example to ask my question. Lets say I want to limit how far user can go up North or South. Unlike real planet, game map is not connected from sides, and in this example is not connected from North to South. If you will try to max zoom out, and go North, drag the map to the North as much as you can, you will see how it runs out of tiles, and shows gray default background instead. I want to limit this North going behaviour.
I guess that radius property in example has to do something with it, but playing with it didn't help.
Is there another option as to how to limit it?
Thanks!
At first: the radius-property used in this script is without any meaning.
Basically you can't restrict the bounds of the map to a given area.
The only thing you can do is to observe a bounds_changed- event and when the bounds are not within the restricted area revert the bounds.
But this may have some undesired effects.
Instead you may disable the dragging of the map and use a custom pan-control, which allows the user a limited panning to north/south
Related
I'm working on the following scenario: I have a geographical location and I need to create a heat-map visualization of travel times (by car) from that location to anywhere around. I'm planning on using Google Distance Matrix API for getting travel duration. But, since it has a limit on the no of API calls, I need to somehow limit the calls.
My plan, so far, is the following: compute the travel duration (basically a numeric value) to a set of points evenly distributed on a grid around the given position (e.g. 0.5km east, 0.5 km east-0.5km north, 0.5 km east-1 km north etc.). This points would represent the centers of square-shaped areas and I will consider the travel duration to the center as the travel duration to anywhere in the area. Display these areas as colored squares on a Google Maps in a heatmap style.
A good example of something that looks alike is this: http://project.wnyc.org/transit-time/#40.72280,-73.95464,12,709 .
So, my questions are:
Does it seem like a good strategy?
Is there a better visualisation strategy for something like this?
How can I create those square-shaped colored areas on Google Maps?
Thanks!
Calculating duration would surely involve traffic flow rather than simply distance. If your calculations are purely on distance you could use the Google Maps direction requests to calculate the distance to each point.
I'm not sure a heat map is the way forward for this scenario.
There a number of way you could achieve this. Here's a few:
a. Use a custom overlay
(https://developers.google.com/maps/documentation/javascript/examples/overlay-simple)
b. Draw polygons on the map and give them different colours based on
the journey duration. This would involve taking the area in question and slicing it up in to polygons however you need to. These polygons could take the same shape as your example. You would need to be rather precise with your latlng. SQL's spacial querys would help you here depending on the tech your using. (https://developers.google.com/maps/documentation/javascript/examples/polygon-arrays)
c. Depending on how specific you wanted to be you could draw circles with different radius value and different colours.
d. You could make custom markers in the shapes you require and add them to the map in the correct latlng in order to fill an area. You could have different markers for different duration and add them accordingly.
I'm sure there are other options as well.
I would like to draw a map of current temperatures (or air pressures, etc.) from many weather stations, with the underlying map still recognizable. the problem is easiest to think of as follows:
I have an array of spot measurements from irregularly spaced dots---think triples of GPS coordinates with one temperature value each. my stations can be very close to or very far apart from one another, and a user may want to zoom in or out. cold should be blue, warm should be red. Ideally, I would like to just pass the array, the color range, and have the rest be taken care of. I would prefer everything to be inside a web browser. The user needs to be able to zoom in, zoom out, move around, and get back to his current location.
I do not even know how to think about this problem. If a user has zoomed out enough, non-transparent dots could be so close as to obscure the terrain. However, zooming in, it would be nice to recognize the dot that is the station itself. This presumably requires some intelligence that realizes how many dots there are, e.g., relative to the density of the display? not sure.
I believe google maps charges for many API calls, so I would prefer using an open map and/or open API that can use different underlying maps. It does not have to be fancy. I don't care about directions, etc.---just a map that is recognizable at most zoom settings, with landmark and street names, and my nice temperature station overlay coloring, so that a user can visualize where it is cold and where it is warm.
(Stations come online and offline, but I don't need to update this more than once an hour. I can place the map measurements into a file that is URL web-accessible.)
is this an easy or a hard problem for the high-level web programmer?
/iaw
after looking around for a long time, I think the best way to do this is with html5 openlayers nexrad.
alas, the docs seem to be a mess. half the examples that I found did not seem to work. it's pretty hit-or-miss. similarly, the openlayers cookbook also seems to be outdated and has incorrect examples, but they did have a reasonably short example of such a nexrad map overlaid on the U.S., that one can further study.
I want to create an online map for a hiking trail, and I have been using my smartphone to collect coordinates from it.
I have many questions regarding what's good practice when it comes to making such tracks, but for starters: it would look much neater if I could edit the readings so that they are right on top any roads in Google Maps. How can I achieve this?
EDIT: I want to find the coordinates that will make a track along a road look exactly as if I'm using snapping/directions even when I'm not.
I've tried tools such as QLandkarte GT and Viking, and with the latter I was able to manually remove excess coordinates and move the remaining ones so that they're exactly on top of roads (inside Viking, using OpenStreetMap). However when I load the edited .kml-file in Google Maps, the roads seem to be in slightly different places and the result is hardly better than before editing.
I tried using the hack that exports GMaps directions as .gpx, thinking I could insert Google's own coordinates along the roads. But the exported file only had coordinates at the turning points with straight lines between these.
QLandkarte GT supposedly has a snap-to-road feature (see answer in link), but I haven't found it and I also don't know how to obtain a vector map of the area.
Then there's Google Earth which people seem to use for this, but again I can't find any track editing features (in the free version).
In short:
How do I edit my existing tracks so that they match roads in GMaps...
OR
How can I obtain new tracks representing roads in GMaps...
...so that the resulting track is as smooth as Google's own directions or other professional GPS-data, when displayed in GMaps?
It seems like it's possible to get these coordinates from Google Maps after all, exporting the directions polyline. I'm not sure how, it seems to involve adding the parameter output=dragdir to the link.
Anyway there's a tool called GPS Visualizer that can create a .kml-file with the wanted coordinates.
Edit: Will accept my own answer as long as it's the only one, but I would still like to know more.
I have an app that finds other users within a 20 mile radius on a google map and associates an icon with each of them. However, I do not want their exact points to be given but rather an approximation. I've wrestled with a few ideas on how to do this:
Only Geocode the Zip Code, make graphic icons for 1-99, use the icon to represent how many results are within the zip code, and use the info window to show hyperlinks to the individual results. The only problem is, I'd like each individual icon to be shown because it just looks a lot better.
Add/Subtract a random number to the lat/lng values stored with each user and add a translucent circle around the icon.
What do you guys suggest?
It depends on the level of privacy you want (the 1st option protects privacy better), but I'd be tempted to go with randomly moving the indicators because it's a more natural representation (people on a map, not groups of people on a map) without too much of a compromise in terms of usefulness.
That depends on how hard you think someone will try to defeat your system.
If you plan to track these positions over time, you give away more information over time than you do in a snapshot. For instance, if you choose a fixed-offset from the center of the circle, it may be possible to find this offset by mapping the path over time to the street map. On the other hand if you continually change the offset, the position may be discoverable by averaging.
Here's one possible scheme based on hysteresis. Leave the visible circle in place until the user exits an invisible bounding circle with a random radius. Then compute a new visible circle with a different random offset, and also set up a new invisible circle with a different random radius. This should generate a visible-circle movement that is almost impossible to reverse engineer, but also avoids lots of jittery movement.
How would I go about creating a Google map that allows the user to zoom beyond the default zoom levels for the map? Would I have to create a new map type that has a greater maximum zoom? Are there any tutorials out there that show how to do this?
Check out the documentation for Google Maps API. One of the things you can do is place more detailed information (an "overlay") on a map. Note that you won't be able to get better imagery than is already there but, for example, the Google Campus itself has quite high-rez imagery.
What you want to work with is the GTileLayerOverlay. It allows you to add custom tiles to the map, providing you have higher resolution versions of the tiles. Is this your goal or were you looking for a way to get back higher resolution tiles from google? (in which case you are out of luck, except for the cases outlined here)