I want to edit the corresponding text/numeric data type columns of a vector through openlayres, when a user click/mouse over a vector. like,
http://dev4.mapgears.com/bdga/bdgaWFS-T.html#
any tutorial page for how to do it?
I gone through it ,
it was difficult for me to understand from its js codes.
-posted in gis.stackexchange
In the example, OpenLayers is getting data from a WFS server with a Postgres/PostGIS backend.
You could try FeatureServer, but the GIS StackExchange is probably the best place to ask for help on this.
Related
I have a big shape file (about 1GB) and I need to display and update data from this file with
an online map (mapbox).
As I understand I need to convert this shapefile into some DB (Spatialite? PostGIS)
and then query it by map BBOX to display by parts.
What is the easiest way to do this? Thanks
Thats a huge topic and depends very much on the usecase. If you want to dive deeper into the topic I would recommend this articel. It describes the underlaying theory and gives a working example for a SQL-Query. For me, it was sufficient to get going with a viable prototype. I think Postgres (with it's Postgis extension) would be a good choice since the data can be directly served as mvt.
I found this site very useful for displaying GeoJson on the fly, it usually copes well with large data, failing that you can import it too. https://geojson.io
With each passing day I'm getting more and more annoyed with Cesium.
There was a project that used QuadTreeProvider to create 3D structures from WFS data.
But the Cesium guys saw the 3D stuff was more lucrative and not only created difficulties to create WFS primitives but created mechanisms to avoid all types of use other than its "Ion 3D tiles".
Now, any kind of question involving 3D they answer with a commercial answer like:
"That sounds like the ideal use case for 3DTiles except for the
dynamic data. Depending on your needs and resources, you could always
contact Todd at todd#agi.com to talk about possibly getting your data
working with 3DTiles."
Of course we can contact Todd. But I don't want to! I want to use free 3D stuff. I WANT to use Geoserver WFS data Todd. Can you allow this for me? Can you allow this project to work again as before?
If you want to make money from your products, you have every right to do so, but don't stop users from creating their own solutions if they don't want to contact Todd.
After all, my question is: How can I use WFS data from Geoserver to create 3D objects in Cesium without need to use Ion / 3DTiles ?
As part of my Master's thesis, I'm trying to run some statistics on which factors affect whether crowdfunding campaigns get funded or not. I've been trying to get data from the largest platform Kickstarter.com. Unfortunately, they have removed all the non-successful campaigns from their website (unless you have the direct link).
Luckily, I'm not the only one looking for this data.
Webrobots.io have a scraper robot which crawls all Kickstarter projects and collects data in JSON format (http://webrobots.io/kickstarter-datasets/).
The latest dataset can be found on:
http://webrobots.io/wp-content/uploads/2015/10/Kickstarter_2015-10-22.json_.zip
However, my programming skills are limited, and I don't know how to convert it into an excel file where I can manipulate the data and run my analysis. I found a few online converters, but the file is far too big for it (approx 300 mb).
Can someone please help me get the file converted?
It will earn you an acknowledgement in my Master's thesis when it gets published :)
Thanks in advance!!!
I guess the answer for this varies massively on a few things.
What subject is the masters covering? (mainly to appease many people who will probably assume you're hoping for people to do your homework for you! This might explain why the thread has been down-voted already)
You mention your programming skills are limited... What programming skills do you have? What language would you be using to achieve this goal? Bear in mind that even with a fully coded solution, if it's not in the language you know, you might not be able to compile it!
What kind of information do you want from the JSON file?
With regards to question 3, I've looked in the JSON file and it contains hierarchical data which is pretty difficult to replicate in a flat file i.e. an Excel or CSV file (I should know, we had to do this a lot in a previous job of mine).
But, I would look at the following plan of action to achieve what you're after:
Use a JSON parser to serialize the data into a class structure (Visual Studio can create the classes for you... See this S/O thread - How to show the "paste Json class" in visual studio 2012 when clicking on Paste Special?)
Once you've got the objects in memory, you can then step through them one by one and pick out the data you want and append them to a comma-separated string (in C# I'd use the StringBuilder) and write the rows of data out to a file on disk.
Once this is complete, you'll have the data you want.
Depending on what data you want from the JSON file, step 2 could be the most difficult part as you'd need to step into the different levels of the data hierarchy.
Hope this points you in the right direction?
You may want to look at this Blog.
http://jdunkerley.co.uk/2015/09/04/downloading-and-parsing-met-office-historic-station-data-with-alteryx/
He uses a process with Alteryx that may line up with what you are trying to do. I am looking to do something similar, but haven't tried it yet. I'll update this answer if I get it to work.
I know this is a somewhat subjective question but I want to throw it out there anyway because if there is some insight that I've missed, asking this question will save me (and hopefully others) a great deal of searching :-)
Basically, what is the best type of database for when you have a number of items interlinked. For example:
A->B->C->D->E->F->G->H->I
And you want to be able to quickly find the shortest path (or the number of paths ideally) between A and I?
I would normally just use a relational database for this, but I'm not sure a MapReduce style database is any better and then I wondered if there was a type of database I hadn't considered altogether...
As always, all help gratefully received :)
This is exactly the sort of thing neo4j is designed for. It's a graph database that provides operations for doing graph traversal and other common operations.
I would suggest looking into MongoDB - It's NOT a relational database, and all your data gets saved and passed as JSON, it's easy scale-able and build for performance, and comes with a couple of tricks up its sleeve as well, like MapReduce build into mongoDB and way way more.
Since the data is saved as JSON you can save objects within objects and arrays well:
{
foo:"bar",
animals: ['cat','dog','fish'],
blog:{
post:"Hello World!",
comments:["this is cool","Hello back"]
}
}
Checkout - http://www.mongodb.org/
or http://www.mongodb.org/display/DOCS/MapReduce/
for more info
How do I take shapefiles and extract lat/lng coords so I can plot polygons on Google Maps?
http://www2.census.gov/cgi-bin/shapefiles/national-files
I asked this question here:
http://groups.google.com/group/Google-Maps-API/browse_thread/thread/18763b4b0cb996c7
and they told me WHAT to do, but not HOW to do it =P
Thx!
It depends on how you need to accomplish this. If you just need a few shapes, you can look up the coordinates in those files yourself. You can use those coordinates to create a GPolygon in Google Maps.
If you need lots of shapes - you'll need to do it programmatically. I would suggest using your favorite language to parse the XML file and retrieve the coordinates for each shape.
I had a similar problem last year when I was developing a screensaver to render presidential polling data. I didn't really want to invest the time to parse the Shapefiles data on the census site (The spec is here if you missed it).
Not sure if I actually saved any time here, but I ended writing a python app to render the 50 states onscreen, trace the edges and then store the data in a simple text format. Not sure if my data is high res enough for your application, but you can grab the data I generated here:
http://www.cannonade.net/pnt.zip
N.B. The data I generate are not latitude/longitudes, but with some scaling you should be able to translate them.
Good luck.
I had better luck using the ARC files at http://www.census.gov/geo/www/cob/index.html
I can't find the webpage right now, but I did find one that had actual code. Google something like "arc to kml" and go from there.