I'm trying to create a custom map using Flutter Web that would be capable of displaying custom statistics for a place for COVID-19.
First we'll have a interface that display statistics for our entire planet:
https://google.com/covid19-map/?hl=en (Just like htisw)
Then the user can click on any country to zoom-in with probably an ease-in transition to see the number of cases in each state or province of that country. Assuming that I am able to fetch the exact co-ordinates of the epicenter in that country, I would like to deepen the shade in those parts in such a way that it lightens out as we move towards areas which have a lower number of cases.
Is it possible in Flutter Web?
I came across this plugin (thanks to this thread on SO Openstreetmap in Flutter?)
https://pub.dev/packages/flutter_map
but it doesn't explicitly say that it supports Flutter Web.
I tried fetching the tiles from OSM(Open Street Map) and displaying the maps on Flutter Web with the help of the example given in the above site https://pub.dev/packages/flutter_map#open-street-map-provider
But it didn't really display anything, maybe because a certain widget or function didn't work as expected.
According to your experience, which is the best way to achieve what I am looking for?
If possible, please describe the answer in such a way as if you were me and trying to do what I am doing.
Flutter_map doesn’t support flutter web.
You may check out the below Flutter Maps widget which has support for all the platforms including web.
https://pub.dev/packages/syncfusion_flutter_maps
Regarding the requirements you have mentioned, you can try the below things.
By dynamically changing the focal point and zoom level based on the click position, the easing effect can be achieved.
https://help.syncfusion.com/flutter/maps/zoom-pan#update-the-zoom-level-programmatically
With the combination of dynamically adding shape sublayers on top of the tile layer and color mapping for that shape sublayers, you may achieve this.
https://help.syncfusion.com/flutter/maps/shape-sublayer#shape-sublayer-on-tile-layer
https://help.syncfusion.com/flutter/maps/shape#range-color-mapping
Related
I'm using Leaflet library in my ReactJS app and I wonder if there is a simple way to recognize if object clicked by user is a building.
Idea that came up to my mind is to check map colour under clicked position.
Does it make sense?
I appreciate your help.
Colleagues in comments advised to give some use-case:
App I'm working on is meant to mark antique buildings with elevation in bad shape so city architecture management had simpler job of searching for them.
Every user of this App can mark such building. To prevent hooligans from corrupting data with senseless points on map I wanted to validate as a first step if clicked point is a building.
I hope it will clarify problem a little bit.
I wonder if there is a simple way to recognize if object clicked by user is a building.
No.
You basically want to run arbitrary point-in-polygon queries against OSM's building dataset, and I will presume that you don't want to host that dataset yourself.
The simplest way to do this is to perform queries to an Overpass API server, passing a is_in query and filtering by the building tag key. The OSM website's query feature functionality uses such a technique.
With this technique you won't have to worry about hosting the data, just about creating the right Overpass API query. Please bear in mind that the Overpass API servers are run by volunteers and their resources are limited.
The second simplest way would be to download a OSM extract of you area of interest, and run the point-in-polygon queries yourself, by whatever means you like (PostGIS' ST_Intersect, turf.js, etc etc).
If you will be using Leaflet, another approach would be to use vector tiles, and set it up in such a way that the buildings thematic layer is interactive. This will require you to be aware of the limitations of the vector tile servers.
Idea that came up to my mind is to check map colour under clicked position.
That is unreliable. Think about labels on top of buildings, or the colour of the edge of the building area, or buildings that don't render with the standard colour (e.g. places of worship, monuments).
I need to display a map of the US and, above that, a layer of states, another of counties and another of places (as per defined by US Census). Also, depending on some criteria, I need to dynamically toggle one layer or another, and to colorize some parts of the layer (e.g. fill some counties in red, others in green, etc). The map itself can be plain simple, I don't need roads or anything that detailed.
My first attempt was done with d3 based on this example, but I'd really like to switch to a tiling-based solution as it seems more responsive, lightweight, smoother and better supported for mobile devices.
I've been looking on the web for a solution (commercial and non-commercial, as a service or locally implementable) but I haven't found one to fulfill all my needs. For example, I've found MapBox which even has a very nice editor, but you can't fine-control the layers you define. I can hide/show a layer, but I can't colorize just a part of it. Google Maps was of course my first option but I didn't find a way to do as above.
Do you know if is there any solution out there that I could use?
I would have a look at the products supplied by boundless. They enable you to use a wide range of technologies and provide the final product in a number of ways. They use Geoserver as a tiling server into which you can output tiles or features depending on what your needs for that layer is.
You can connect to it using ESRI, Quantum GIS or use the included web based map. They are open source so there is a community version that can be used for free or a commercial version that is basically the same but comes with enterprise support.
You can find them here.
Can anyone suggest a good javascript library for displaying and navigating huge images in HTML?
I need a way for my users to navigate some custom maps[1], with zooming and dragging similar to Google Maps. I need the solution that works offline as I'm embedding it in an iPad html (phonegap) application[2].
I actually already have this working (mostly) with PanoJS. But it lacks a way to float widgets above items in the map, e.g. Float a button over an area of the map that can be clicked to navigate to somewhere else.
I am able to split up my large images into tiles. I'm just looking for a slightly more advanced viewer than PanoJS, without having to build it myself :)
Anyone got any ideas? Some have suggested OpenLayers. War stories?
Thankyou,
dan
[1] The maps are stylized and don't map to real world coordinates.
[2] All the images and tiles are supplied with the application and are loaded locally.
In the end I went with leaflet.js. This was able to give me the map, layers, markers and the other bits and pieces I needed. (http://leaflet.cloudmade.com/)
I spent quite a bit of time with ModestMaps.js along the way. That's a great library, but quite low level. Leaflet ended up being the best mix.
Thanks everyone for their help.
I started to create a script that allows me to split a big image into small pieces,to zoom, drag , etc.
I want to know what are the possibilities to load the small images just in the active area like in Google Maps (visible). I thought to try to determine the approximate location of one element with some calcules and to determine the element with document.elementFromPoint, but it's not a cross browser solution.
Another solution could be: loading from the beginning just the images from active area and when the user drag or zoom the script must calculate the elements that are new in active area.
see here what I mean active and inactive area: http://i.stack.imgur.com/mRY5K.jpg
PS: I searched the entire site but I did not found an answer. I read also this topic : How does Google Maps work? , but I would like to develop myself the script. (I don't need the complexity of Google Maps, just few features)
Look into DeepZoom. Its an opensource project that does exactly what you want. Its written for .net... but i think it might be what your looking for
DeepZoom is created by SeaDragon and is built for silverlight but they also have a Javascript implementation too called SeaDragon Ajax
I want to create a map dynamically and display it on the website. You can call it to be more of a graph than a map. Here I take the source and destination from the database. There can be many sources to a destination or many destinations for a source or both. Also there can be many other locations directed to/from source/destination. Source and Destination will always be there. But other locations are optional. So for example the route could be
L1 --> L2 --> Source --> Destination --> L3 --> L4.
where L1-L4 are locations (optional)
I want to depict this diagrammatically on a website. The user should be able to click on a each location/path (depicted as the arrow line above) and a popup should be opened. In the popup some data editing can take place. Also along the path(arrow line) some data has to be displayed. Basically all HTML,JS functionality should be available for this diagram.
Can someone please suggest me which language I can use for this?
I checked out some of the map APIs. But they expect some kind preloaded image to be present. That is not possible in my case.
The site I'm working on similar to any air fare info site, where we select multi city and get different rates for different airlines. I want to show this graphically with nodes representing locations and lines representing paths and should show rates along paths and stuff like that.
Any pointers will be appreciated.
Thanks
Some of your options are: SVG, HTML Canvas, or HTML+CSS. Given your desire to track events per object, I would rule out HTML Canvas: binding events to objects in a retained drawing system is much easier than manually processing events based on mouse position.
I would recommend using either SVG (if you can limit yourself to browsers that support it) or a drawing API like Raphaël to abstract support over SVG and VML for IE. You will have far more flexibility of drawing and hit detection than using HTML divs plus backgrounds.
Although I haven't used it, Google found the Joint library (that uses Raphaël) for a higher abstraction than the drawing level. Perhaps this meets your needs.
If I understand you correctly, it sounds like the google maps api would work for you:
You can find more info here. here
Additionally, you may find this info useful.