10

After seeing a recent video by the Google Devs I decided to do a regional map of the UK. There were a couple of possibilities mentioned on this site that I've since had to dismiss*

So I ended up using this site (example page of data downloads): http://mapit.mysociety.org/area/11804.html

Notice the GeoJSON download as the third link down? Its about a 1Mb file size. When I first tried using it with my map:

function initMap(){
    var ukc = new google.maps.LatLng(54.8, -4.6);
    var mapOptions = {
        zoom: 5,
        center: ukc
    };
    map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
    map.data.loadGeoJson('http://local.mapsite.com:8080/app/jsondata/eastern.json');
}

$(document).ready(function(){
    initMap();
});

I got the above error: Uncaught InvalidValueError: not a Feature or FeatureCollection

Fix Attempt 1 - Google it

Googling the error came back with nothing useful.

Fix Attempt 2 - Shrink it

I thought maybe it was the sheer size of the beast so I shrank it using mapshaper.org to a more manageable 10K. Still no luck!

Fix Attempt 3 - Lint it

Maybe my GeoJSON was badly formatted? But how could it be considering it was right there working on mapit.org but I found this wonderful site for linting GeoJSON data: http://geojsonlint.com/ - The linting worked! Apparently the GeoJSON worked so well that it drew my polygon of East Anglia on the UK in all its glory (note geojsonlint uses OpenStreetMap). But still No Luck

Fix Attempt 4 - TopoJson

Hoping I could combine the regions and compress at the same time I thought desperately that topojson would work. I tried - I still got that same error. Here's a link to my topojson file shared on Google Drive: someregions.json No luck.

Fix Attempt 5 - Add Feature code to start of JSON

The current GeoJSON file starts {"bbox":[-0.745702,51.448473,1.767999,52.98991],"type":"GeometryCollection","geometries":...

I added:

{"type": "Feature", "bbox":[-0.745702,51.448473,1.767999,52.98991],"type":"GeometryCollection","geometries":

Fix Attempt 6

Retry different regions as they donm't contain the bbox parameter near the start but simply start { "type": "Polygon", "coordinates": [ [ [ -3.155785, 53.427385 ], [ -3.151533, 53.427328 ], [...

Still no luck.

In (Failed) Conclusion

Even though I proved my file was small enough, linted and worked elsewhere I still got those infuriating error messages from the console when attempting to put them on my map.

Uncaught InvalidValueError: not a Feature or FeatureCollection

Here is my shrunk GeoJSON file publically shared via GDrive: https://drive.google.com/file/d/0B42Aec8RKcHtNVNZZUxqV0Y5Rkk/edit?usp=sharing

My next attempts will involve topojson to compress all regions into one with internal borders but I wanted to check here first to see if anyone knows what my problem could be? Because that may be another few hours of futile energy wasted.

* Attempting to use Ordanance Survey data failed as they provided SHD data and not SHP as stated in a previous question on the subject. So I couldn't convert it into GeoJSON using ogr2ogr.

3
  • 1
    Just to note that Ordnance Survey definitely do provide SHP data, as that's what we use to import into MapIt :) MapIt also has a simplify_tolerance parameter to reduce the complexity of the returned shape. Commented Mar 26, 2014 at 12:26
  • Hi @MatthewSomerville. I followed the instructions here which recommends finding the Ordinance Survey's SHP data here but found only the SHD data files. Any chance you could point me in the right direction?
    – RustyFluff
    Commented Mar 27, 2014 at 10:03
  • 1
    I see the comment you left on that answer received a response which answers your question here - you need to tick the box on the page linked to, and submit the form to be sent an email to download the Boundary-Line data. Alternatively you can get it from the cache of that data we maintain at parlvid.mysociety.org/os Commented Mar 27, 2014 at 10:39

5 Answers 5

18

The specification for GeoJSON can be found at http://geojson.org/geojson-spec.html Relevant (though experimental) Google Maps API documentation can be found at https://developers.google.com/maps/documentation/javascript/3.exp/reference#Data

So it looks like for GeoJSON to be acceptable by Google Maps, you need to wrap a Polygon (or similar) returned by MapIt in a Feature or FeatureCollection, here's an example for bermuda-triangle:

  { "type": "FeatureCollection",
    "features": [
      { "type": "Feature",
         "geometry": {
           "type": "Polygon",
           "coordinates": 
              [
                [
                  [-80.190262,25.774252],
                  [-66.118292,18.466465],
                  [-64.75737,32.321384],
                  [-80.190262,25.774252]
                ]
              ]
         }
      }
    ]
  }

for the data provided by http://mapit.mysociety.org/area/11804.html it has to be:

  { "type": "FeatureCollection",
    "features": [
      { "type": "Feature",
         "geometry": /** paste here the complete output of 
                         http://mapit.mysociety.org/area/11804.geojson **/
      }
    ]
  }
3
  • MapIt returns valid GeoJSON, as far as I can see. As the spec you link to states, "A GeoJSON object may represent a geometry, a feature, or a collection of features." and "Each of the examples below represents a complete GeoJSON object." Could you point out where a Polygon must be wrapped in a Feature and a FeatureCollection to be valid? It sounds like Google Maps mandates Feature or FeatureCollection, though I can't find any API docs on that. Commented Mar 26, 2014 at 12:31
  • The reference may be found at developers.google.com/maps/documentation/javascript/3.exp/… (note that Data belongs to the experimental API-version, maybe the documentation will be more detailed in the future). Most of the methods there require a feature(of course you need a FeatureCollection when you have multiple features)
    – Dr.Molle
    Commented Mar 26, 2014 at 23:00
  • So the Google Maps API mandates Feature or FeatureCollection, as I suggested, but that is not the same thing as saying the GeoJSON returned by MapIt is "wrong", nor that according to the GeoJSON specification that a Polygon must be wrapped in a Feature and FeatureCollection. Commented Mar 27, 2014 at 10:37
17

I had the same problem (or at least similar) and solved it by introducing one extra step.

Origin of the data: My semantic Network delivers on a first round request the data about the caves in Southern France in GeoJSON format. This is directly imported via:

map.data.loadGeoJson(theUrl);

As we might want to work independent of the semantic network with these data (the app is a thick client) the caves are locally stored via jStorage. Iterating of the features of the map and storing these objects directly in jStorage failed because of circular references. I made a handcrafted routine (not generic enough but suiting the purpose) to transform the map.data.Feature into a javascript object that could be stored.

When getting the data from the store:

var cave =  $.jStorage.get(key);
map.data.addGeoJson(cave); 

throws the Uncaught InvalidValueError: not a Feature or FeatureCollection error.

But:

var geojson = JSON.parse(cave);
map.data.addGeoJson(geojson);

Works fine.

My interpretation is that the function addGeoJson needs a javascript object and not a string.

Sample geoJson (the orignal "cave") value:

{ "type": "Feature", "geometry": {"type": "Point", "coordinates": [5.368743302306143, 44.0421921072459]},"id": "84.MON.014", "properties": {"nom": "Aven du Grand Guérin", "nid": "7b4703-f387f6f544-0750e59f441be7bb30a7e097c5d725f7", "nature": "Aven", "nodeTime": 1400743203325, "dataId": "5b66137c-1461fdfe5ca-f528764d624db129b32c21fbca0cb8d6", "status": 1}} 
1
0

If you are looking to load the data to a JavaScript variable then use this

var map = new google.maps.Map(document.getElementById("googleMap"), mapProp); var data = map.data.loadGeoJson("GeoJSONfilename.geojson");

googleMap is the div id where you want your map to be presented, and GeoJSONfilename.geojson where you saved your GeoJSON data.

1
  • var mapProp = { center: new google.maps.LatLng(41.152036, -81.336186), zoom: 12, mapTypeId: google.maps.MapTypeId.ROADMAP }; Commented Jun 13, 2018 at 17:16
0

I had the same error, but the problem was something very simple. On my GeoJSON, instead of

"type": "Feature"

I had

"type": "feature"

(note the lowercase 'f')

Once I fixed this, the error was gone.

0

I had the same error message. My .json file missed one line of code on line 2: "type": "FeatureCollection",

Before I had in my .json-file:

{
  "features": []
...
}

It fixed it for me with:

{
  "type": "FeatureCollection",
  "features": []
...
}

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