In this video we will show you how to convert KML format into GeoJSON quickly in 3 easy steps in less than a minute. 1) TERRAFORMER Note: use in node. Tile rendering library for node. Using Oracle Map Builder you can convert shapefiles to geoJSON files. Test this data out by importing it again into. Our online converter of Scalable Vector Graphics format to Topological GeoJSON format (SVG to TopoJSON) is fast and easy to use tool for both individual and batch conversions. json2csharp is joining forces with quicktype to offer new and improved features including JSON attributes, PascalCase properties, modern C# syntax (nullables, expression members), Dictionary detection, class deduplication, and more. For the rest of the article I will use this type of index and focusing on GeoJSON. If you could share this tool with your friends, that would be a huge help: Tweet. The following image. Put the shortcode into the post. Once both are installed you can use gdal_translate to do the actual conversion. First step is to convert to a web-friendly format, GeoJSON. What is Ogre? Ogre is a web client (service) that translates spatial files into GeoJSON using the ogr2ogr command line tool for use in JavaScript web applications and frameworks. The 2 forms on top of this page are live. Example 22-1 A Table With GeoJSON Data. geojson file? What program do I need to open a. Popup, default None) – Input text or visualization for object displayed when clicking. Your JSON input should contain an array of objects consistings of name/value pairs. GeoJSON is a JSON-based a data format used to represent geographical data. 39GB, our buildings layer shapefile greatly exceeded Mapbox’s 260MB shapefile upload limit. I’ll show you a few places where you can find free geographic data online. Conversion of KML format to JPEG picture format basically represents export of rendered version of the data from. Items you create in ArcGIS Online. 15 Export map as images; 1. This application KmlToGeojson, converts Kml and Kmz files into a GeoJSON representation. geoJson has been passed an options object. #' Geojson to sfc #' #' Extracts geometries from GeoJSON and returns an `sfc` object #' #' @param geojson string or vector of GeoJSON, or a URL or file pointing to a geojson file #' @param expand_geometries logical indicating whether to unnest GEOMETRYCOLLECTION rows. naturalearthdata. You can also use kml2geojson as a library. TopoJSON is D3's preferred format, which is why Power BI users have suddenly found themselves learning more about it after the Shape Map was released. Great news is this is possible! and i n this blog we will discuss about how to convert an image to a geoJSON file format. The format has "made the big time" in some sense, as the final specification is complete and Safe Software announced full support for it. Converter also supports more than 90 others vector and rasters GIS/CAD formats and more than 3 000 coordinate reference systems. In this tutorial we are going to see how to create custom GeoJSON world map for HighMaps using QGIS. Try it free. bat script takes a folder name as input and recursively scans that folder for all ADF files and attempts to create a GeoTIFF for each. Import and convert map boundary files. Vector layers are things like points, lines, polygons…basically anything that’s not a large image / historic map / tiff. The WCT provides tools for background maps, animations and basic filtering. Share this: google jsapi google map Google Places API HTML5 image database iphone j Java DB javaScript jQuery load. Mapping solutions for your business – 18 years Gismaps Viewer is a GIS software to generate thematic maps and view satellite images. A simple tutorial on the use of the python-geojson library. Mapbox is a popular source of maps and tools for building mapping applications. Learn how to import GeoJSON data from either a local or remote source, and display it on your map. Convert GeoJSON to TopoJSON; Different ways to convert Shapefile to GeoJSON I. Take a look at the. So markers are fine. In this example I used the data from Natural Earth and I wanted to extract specific countries from the “Admin 1 – States, Provinces” data set and convert the ESRI shapefile to GeoJSON. pointToLayer always accepts two arguments: the GeoJSON feature, and a LatLng object representing its. I have written a Django app that would get some input and give you an image as output. What formats does it support? Currently Ogre supports the following transformations:. Now you want to make a web map. A-VEKT Image CSV Converter is a software to convert an image to/from a CSV file. Use JPEG Files in ArcGIS. Oracle DV supports custom map layers defined in GeoJSON formats. Your GPS device may be able to import them in. So markers are fine. GeoJSON encoding/decoding¶. Smart PDF to Image Converter : PDF to Image Converter is a component for batch converting PDF documents into single page or multi-page raster images such as TIFF or JPEG (pdf to jpeg converter). The first row showcases the original data from the Florida Geographic Data Library, converted to GeoJSON (8. However, if you have control over the process that generates the GeoJSON in the first place, you might use these techniques to put the styling information directly in the JSON. All you need to do to use it is to call this line "import json". From time to time I come across an interesting data set in GeoJSON format that I want to quickly view in Bing Maps. The Bing Maps API's make it easily read these files, but if I just want to quickly view the data I don't really want to write an app each time I want to view a GeoJSON file. Unlike the once popular XML, JSON. Basic Usage. In addition to the GeoJSON data, L. The coordinate values exist as arrays stored as a string in a CSV file. Convert to Geopandas Dataframe. It works well with Terraformer for converting data between different geo formats, and geoservices-js for making advanced requests to ArcGIS REST services such as place finding and reverse geocoding. Query / Data. Great! This session is the first part of a series that introduce Leaflet, a Javascript library used to create interactive, web-based, mobile-friendly maps. How do I convert an SVG file to GeoJSON format? Desired Outcome: I want to make a choropleth map using something like D3. This interface attempts to ease the pain of downloading 30-meter resolution elevation data from the Shuttle Radar Topography Mission. Usually, If the JSON file is small or has a simple structure then I would use any of the online converters to quickly convert it to CSV. For more information on working with data from the NYC Space/Time Directory, see the Data & Tools repository on GitHub. You can vote up the examples you like or vote down the ones you don't like. Before I begin the topic, let's define briefly what we mean by JSON. shared borders between counties and municipalities). You can easily convert KML to GeoJSON here. Browse 2+ GPX APIs available on RapidAPI. I just want to convert OSM data to GeoJSON where it is pretty simple with node and way tags of OSM data, but relation which is giving complex can't find the logic to convert OSM relation to GeoJSON format, especially how to form coordinates parameter of GeoJSON based on their relation member roles (. kml files to GIS shape. Convertio — advanced online tool that solving any problems with any files. image All images latest This Just In Flickr Commons Converting a GeoJSON file into a Shape file using mapshaper. In Mapbox, you can add a GeoJSON object to your Layer as a data source so it knows where and how to put the items on the map. Help: How to install township and range. projections (functions that convert from latitude/longitude co-ordinates to x & y co-ordinates) geographic path generators (functions that convert GeoJSON shapes into SVG or Canvas paths) Let's look at these one by one. Embroidery digitizing is possible with the help of a software that is purposely made to convert standard image files to embroidery machine readable formats, or in simple words, convert a JPG image or logo to embroidery file. kmz-geojson - Convert KMZ to GeoJSON #opensource. jsWhat we need to do next is convert our geojson input format to a THREE. In a blog post from November last year I looked at various strategies to minify GeoJSON files. The steps below are the workflow I went through to create a seamless, collar-less USGS topographic map of Oahu. Potrace can currently produce the following output formats: SVG, PDF, EPS, PostScript, DXF, GeoJSON, PGM (for easy antialiasing of pixel-based images), Gimppath, and XFig. To convert shapefiles into TopoJSON, you can use mapshaper, a tool for shape simplification and conversion from one geo format to another. Those types of images are raster layers. If you wanted to know what atom number is that Carbon next to the Nitrogen, make sure to have the “Image Map Style” to “Atoms”, similarly to see the connectivity by selecting “Bonds”. kml file to a raster picture (. It works well with Terraformer for converting data between different geo formats, and geoservices-js for making advanced requests to ArcGIS REST services such as place finding and reverse geocoding. addTiles, addMarkers, addPolygons) to modify the map widget. FeatureCollection(). # A script to convert vector data into a weighted raster overlay suitability map for prioritizing Libyan refugee camps locations. The tool enables National Environmental Monitoring Sites Register data custodians to convert CSV files into GeoJSON format before uploading to NEMSR. Potrace is a utility for tracing a bitmap, which means, transforming a bitmap into a smooth, scalable image. Web Server can produce response in GML, GeoJSON, XMLetc after running a spatial query. GeoJSON, as defined by its spec, is “a format for encoding a variety of geographic data structures”. Then you can export it out of ArcGIS as either a shapefile or GeoJSON. The web site is a project at GitHub and served by Github Pages. KML file extension is a Keyhole Markup Language file. without converting the data to csv but directly into GeoJSON. bmp, png, tif, jpg and gif formats are supported. It uses the exif-js/exif-js library for reading EXIF image metadata. loads functions. Output Coordinate System. This may be dictated by your target environment, but if not there are several options available. If no arguments are specified, this method returns the current features array, which defaults to null. Map tiles are provided by default through OpenStreetMap, or MapQuest (with an app key). Alpha Channel transparency for a PNG file is supported. Individual snippets, not a whole document. GeoJSON, as defined by its spec, is “a format for encoding a variety of geographic data structures”. In addition to the GeoJSON data, L. pointToLayer always accepts two arguments: the GeoJSON feature, and a LatLng object representing its. Call us toll free: call1 866-658-7527. I am passionate about open source GIS and hope that this site can act as a spring board to creating some local interest in open sourcce GIS, and hopefully provide an opportunity for the GIS user community in Hawaii to share and learn from each other. Evaluation Maps Converter. linestring: Convert a coordinate array from GeoJSON into an OpenLayers. Next we will review geojsonio, a tool used for visualizing GeoJSON on the browser. 100% free, secure and easy to use! Convertio — advanced online tool that solving any problems with any files. In Windows Explorer, when you drag and drop a folder onto a batch file, the folder path is passed as the parameter to run that batch file with. svg2geojson. Load the GeoJSON into Google Maps and set up click events and interactivity. parseCoords. Our online converter of Scalable Vector Graphics format to Topological GeoJSON format (SVG to TopoJSON) is fast and easy to use tool for both individual and batch conversions. Simple Maps Using GeoJSON and Tile5 I've been wanting to post about GeoJSON for a while now because I like what the standard provides in terms of simplifiying interoperability. What is Ogre? Ogre is a web client (service) that translates spatial files into GeoJSON using the ogr2ogr command line tool for use in JavaScript web applications and frameworks. IEM GIS Information. He recently modified my SDO2GEOJSON function. List data in well-orgnized table when JSON is parsed. You can get this using jQuery's default. convert json to kml free download. Those types of images are raster layers. GeoJSON map is just a single file, so you would only need to select one file for the conversion. This example uses ol/layer/VectorImage for faster rendering during interaction and animations, at the cost of less accurate rendering. This means that a user has to spend additional time uploading files he needs converted. To add and remove your GeoJSON data to and from the map, call addLayerToMap() and removeLayerFromMap() respectively. The three files required have the extension. Only one such document is inserted here. Convert GeoJSon to Sdo_Geometry. Data insight visualization and collabration in minutes. A more detailed step-by-step instruction is in the tutorial here, How To Convert GeoPDF to GeoTIFF using AcrcGIS. - Optionally create several GeoJSON files of FeatureCollections, one for each KML folder Installation ===== ``pip install kml2geojson`` Usage ===== At the command line type ``k2g --help`` for instructions. geojson file? How to open. By now only polygons, paths and points placemarks can be converted to GeoJson, Multigeometry is not supported yet. esri-leaflet: A lightweight set of tools for working with ArcGIS services in Leaflet - (example: Using GeoJSON with Leaflet) geojson projects on Github. Shouldn't your json. Maybe not the best solution, but since ESRI Fature Collections can only contain one geometry type, it’s the best I could think of. Saving in JPG format an image loses its quality, because of the size compression. This application KmlToGeojson, converts Kml and Kmz files into a GeoJSON representation. Example from ipyleaflet import Map Map (center = [34. Convert the input data to a Three. There are several open source tools for converting other geospatial data formats to GeoJSON, including:. I hacked a C++ tool for converting GPX files to GeoJson, because the only one I could find used Node. Online JSON tools is a collection of useful JSON utilities for working with JavaScript Object Notation data structures. Convert a KML document to GeoJSON. Great! This session is the first part of a series that introduce Leaflet, a Javascript library used to create interactive, web-based, mobile-friendly maps. osmtogeojson is yet another OSM-to-GeoJSON converter. How do I convert an SVG file to GeoJSON format? Desired Outcome: I want to make a choropleth map using something like D3. PixelFormat. json) Conversion result implemented in Google Maps, using data of my hometown Deinze, Belgium To convert ESRI shapefiles to geoJSON (which you can perfectly use JavaScript and thus pass on to Google Maps, see screenshot above) you will need GDAL (Geospatial. Dependencies. There are no ads, popups, or nonsense, just an awesome JSON screenshot creator. Converter also supports more than 90 others vector and rasters GIS/CAD formats and more than 3 000 coordinate reference systems. Vector Image Layer Example of rendering vector data as an image layer. I am working on a class library in C# to convert WKT to GeoJson. Hi ashish,am supposed to upload an image to picasa web album from google app engine. kml files to GIS shape. Programs used to perform the conversion from jpg file to csv format. geojson file be opened, edited or printed? How can I convert. Mapzen's vector tile service delivers worldwide coverage of OpenStreetMap base layer data, and is available in GeoJSON, TopoJSON, and MVT binary format. Welcome to the open learning GIS lab. It is fast and easy, as you can provide it with a file on your computer or with a remote URL. A very usefull option is the possibility to send the query to JOSM. 0) – How much to simplify the polyline on each zoom level. When it comes time to export those polygons into shapefiles or GeoJson, I seem to be getting those polygons tilted by 90 degrees and flipped. polygon: Convert a coordinate array from GeoJSON into an OpenLayers. Output Coordinate System. Image Converters. NET library provides an easy, and de-facto, standard way to convert (serialize). Here is what the data looks like:. TopoJSON introduces a new type, "Topology", that contains GeoJSON objects. smooth_factor (float, default 1. generate c# classes from a json string or url. In the Returning spatial data in GeoJSON format - Part 2 you can see how to export other spatial types. shp ogr2ogr -f "GeoJSON" working/zipcodes. In a blog post from November last year I looked at various strategies to minify GeoJSON files. Google Maps, Saved Places JSON to KML and Google Search History JSON to KML. GEOJSON file extension Information that help open, edit, and convert. @yoon-jong-hwan 1) You have to export the file as kml (not kmz which is just zipped kml and the images folder), 2) if there are incons or pictures in kml, all images have to be hosted somewhere and linked by their full urls (they won't be uploaded to Wind. Load the GeoJSON into Google Maps and set up click events and interactivity. You can also use the Query Editor to create formulas to connect to JSON files. Try it free. Path that we can use in our scene. Key Features Convert KML to AutoCAD(dxf file). Converting csv files to php and insert them to database and to make them readable form backend in opencart. Displays townships, sections, and quarter-quarter sections (western states have quarter/quarters mapped, central states do not). View GPX file on map + elevation This page allows you to display a track from a GPX file recorded with your GPS (using maplorer or any other software writing GPX files, which is pretty much standard). Convert GeoJSon to Sdo_Geometry. Basic Usage. shp # merge two shapefils. loads functions. TopoJSON introduces a new type, "Topology", that contains GeoJSON objects. They are extracted from open source Python projects. 375 and the one on the right shows it set to 3. Convert JSON online - Convert JSON data to CSV, XLS, XLSX, ODS, HTML or PDF file. Note: Some item types are automatically added to My Content when you create and save them through a related app or workflow, but they can't be added through Add Item. A shapefile is actually a collection of at least three basic files:. The first row showcases the original data from the Florida Geographic Data Library, converted to GeoJSON (8. Is there a way to convert SVG files, e. GeoJSON map is just a single file, so you would only need to select one file for the conversion. My question is regarding how to do the exact same thing using python code. All JSON tools are simple, free and easy to use. pointToLayer always accepts two arguments: the GeoJSON feature, and a LatLng object representing its. Part 2: Using GeoJSON file-size issue, comparison, tiling, and display. The file is usually called Saved Places. It requires that you hand-edit your SVG to add two XML tags that associate an SVG location with a lat/long, and it provides a command-line tool to convert the file. Kml2Shp Online: Convert from Google Earth to Shapefile. Hence you can't directly send any image using JSON. ) or a GeoJson object in form of a character string. (See also: download free shapefile maps). Example from ipyleaflet import Map Map (center = [34. KML to GeoJSON converter is available at. topojson: Convert GeoJSON to and from TopoJSON; join data from CSV. geojson file extension. This application allows you to convert your Google Earth files (*. This tutorial uses the map below to illustrate various techniques to import data into maps. The GDAL_Convert_All_ADF_2_GeoTIFF. You can convert graphics you draw on your map into shapefiles or geodatabase feature classes. To add and remove your GeoJSON data to and from the map, call addLayerToMap() and removeLayerFromMap() respectively. For [leaflet-image] upload an image, and copy the URL from the right-hand side. They are the vector data equivalent of image tiles for web mapping, applying the. There are two great online tools for easily converting an ESRI Shapefile Map to GeoJSON format, or vice versa. You can also force double quotes around each field value or it will be determined for you. Once both are installed you can use gdal_translate to do the actual conversion. help would be great! Another common option is to store the location of an image inside your. It is fast and easy, as you can provide it with a file on your computer or with a remote URL. This may be dictated by your target environment, but if not there are several options available. Render Geographic Information in 3D With Three. response property holding an XML DOM. If you are like me that often produce web based maps often, you will definitely come across situations were you have to convert the most popular geospatial file format (Shapefile) into the most popular web programming language file format - JSON (thta is: GeoJSON in our case since we care more about location elements). GeoJson KML To DXF Converter allows batch convert Keyhole Markup Language format to AutoCAD Drawing Exchange Format format (KML to DXF KMZ to DXF GeoJosn to DXF) is fast and easy to use tool. Need to convert CSV file? Our online tool will help you with this! Easy to use, no registration and 100% secure to use. (This approach is not recommended for applying styling in R; instead, use the approach described above where we convert to sp first. Here, in this article I’ll show you how to convert JSON data to an HTML table dynamically using JavaScript. Read here what the GEOJSON file is, and what application you need to open or convert it. Executable programs that run in their own memory space. Our online converter of JavaScript Object Notation format to ESRI Shapefile format (GeoJSON to SHP) is fast and easy to use tool for both individual and batch conversions. Next we will review geojsonio, a tool used for visualizing GeoJSON on the browser. Note: The built-in TileStache Vector provider (new in version 1. You can easily convert KML to GeoJSON here. So, you know some basics about webpages and their elements. Advanced users can convert GEOJSON to JPG via command-line interface in manual or automated mode. This example uses ol/layer/VectorImage for faster rendering during interaction and animations, at the cost of less accurate rendering. I am getting shapes in WKT out of MSSQL. These plugins can also be installed directly from the QGIS Plugin Manager within the QGIS application. The purpose of this package was not only the implementation of functions to convert from and to geojson objects, but also the development of web applications based on geojson objects / data, which I'll explain later in the blog post. Convert to Geopandas Dataframe. Sorry if this is the wrong place to ask but I wondered if there was a way to convert an image (jpg/png/tiff/geotiff etc) to a massive group of polygon squares/shapes in a kml/geojson file and retain their lat/lng coordinates?. isValidType: Check if a GeoJSON object is a valid representative of the given type. See Serializing Django objects for more information on serialization. Dependencies. More means better performance and smoother look. Connect systems, transform data, and automate workflows. I’ll show you a few places where you can find free geographic data online. geojson But one can also use the library in javascript (browser or nodejs) projects. Demonstrates how to attach an image to a Vector layer, and let it resize based on the zoomlevel. In Windows Explorer, when you drag and drop a folder onto a batch file, the folder path is passed as the parameter to run that batch file with. GeoJSON data structures are always valid JSON objects, so they can be stored and queried using Azure Cosmos DB without any specialized tools or libraries. Import and convert map boundary files. The tool help you to convert CSV data into GeoJSON data. If I save the image as is, it will be saved at the screen resolution, which will result in poor resolution (pixelation) at the edges. It's written as a javascript library, but can also be used as a command line tool: After installing it via npm install -g osmtogeojson you can use it like this: osmtogeojson in. Your parcel boundary is now a polygon! Method 2: Moving on to GeoJSON. No ads, popups or nonsense, just a JSON to text converter. As you can see with new FOR JSON clause we can easily output any JSON format such as GeoJSON. In Mapbox, you can add a GeoJSON object to your Layer as a data source so it knows where and how to put the items on the map. geojson file? What is. These are the cases when an image's size matters more than image's quality. You can edit an image with Excel by converting to CSV. I wish I could just load GeoJSON and/or JSON files into ArcMap/PRO without having to convert them (maybe there is a way that I don't know about?). convert_to/from_extras have been fixed to not add quotes around strings (#2930) Updated CKAN coding standards (#3020) and CONTRIBUTING. You can upload GeoJSON files to Mapbox Studio as either datasets, or as tilesets that you can use in a custom map style. I’m using VBA-JSON library for parsing JSON data. The first argument, doc, must be a KML document as an XML DOM - not as a string. Convert Kml to GeoJSON format. Convert a coordinate array from GeoJSON into an OpenLayers. parseCoords. More means better performance and smoother look. Andy Versal is a reader of this website. Run Swift is a web tool where you can easily try Apple's Swift language online. Fork me on github. GeoTiff and GeoJSON. Oracle DV supports custom map layers defined in GeoJSON formats. Great news is this is possible! and i n this blog we will discuss about how to convert an image to a geoJSON file format. The 2 forms on top of this page are live. Data Converter. 1 had support for geopdf conversion, but it did not work on USGS topos. polygon: Convert a coordinate array from GeoJSON into an OpenLayers. For this we use org2ogr (with defaults) using the following code: ogr2ogr -f "GeoJSON" township. To facilitate analysis and mapping, the data is available in coma-separated values (CSV) file format, ESRI Shapefile, and GeoJSon. pointToLayer always accepts two arguments: the GeoJSON feature, and a LatLng object representing its. You can upload GeoJSON files to Mapbox Studio as either datasets, or as tilesets that you can use in a custom map style. image All images latest This Just In Flickr Commons Converting a GeoJSON file into a Shape file using mapshaper. Uppercase or Lowercase Text Tool. About MyGeodata Converter. convert KML and GPX to GeoJSON Latest release 0. The following code chunk shows the. 375 and the one on the right shows it set to 3. Start > Read Me First. Smart PDF to Image Converter. Returning to Design Studio. This example creates table j_geo, which has a column, geo_doc of GeoJSON documents. I need to put images in json and ive been looking around the internet and reading things about base 64 and data uri but there have been no tutorials so I have no idea how to implement these concepts. Here Are Best 5 Websites To Convert KML To GeoJSON Online: AcuGIS. ArrayOfBounds: An Array containing two items, each as Arrays of Lat/Lng points corresponding to North East and South West Lat/Lng points over which you want your SVG to be placed on a map. If no arguments are specified, this method returns the current features array, which defaults to null. Okay, great, you've got some files loaded up and showing in a map! Now let's focus on how to export the vector layers. The From PDF toolset contains tools that will export a PDF file to a Tagged Image File Format (TIFF). They are extracted from open source Python projects. Andy Versal is a reader of this website. This service returns map images in common image formats such as JPEG, GIF, PNG, and others. The file is usually called Saved Places. Using a combination of Oracle tools, users can convert an image of a layout into GeoJSON. Free 30-day trial. What application can open. The exif2 is a standealone fuction to read EXIF image metadata in a set of images and to convert them to GeoJSON. Designed for self-hosting and online map publishing with WMTS, custom coordinates, georeferencing and more. Batch Convert CGM Images. Sqlify's New Pay As You Go Pricing Convert between CSV, JSON and SQL files in PHP using the Sqlify API Convert and flatten JSON to CSV or SQL using JSON path expressions One-liner to migrate data from MongoDB to MySQL from your shell Uploading a big file to the Sqlify API in chunks. JSON is a text-based, human-readable format for representing simple data structures and associative arrays (called objects). GeoJSON is a format for encoding a variety of geographic data structures using JavaScript Object Notation (JSON). Saving in JPG format an image loses its quality, because of the size compression. projections (functions that convert from latitude/longitude co-ordinates to x & y co-ordinates) geographic path generators (functions that convert GeoJSON shapes into SVG or Canvas paths) Let's look at these one by one. ) or a GeoJson object in form of a character string. Invalid GeoJson (Data was not JSON serializable) python,json,geojson. You can edit an image with Excel by converting to CSV. you will use at least points if your image is related to a flat. About MyGeodata Converter. Vector layers are things like points, lines, polygons…basically anything that’s not a large image / historic map / tiff. Learn how to convert static images into interactive shapefiles. Part 1: The differences between Raster & Vector Images on Map/Openlayers. It's written as a javascript library, but can also be used as a command line tool: After installing it via npm install -g osmtogeojson you can use it like this: osmtogeojson in. NET class to JSON data, and JSON data back to. Leaflet GeoJSON Tile Layer Example. It is today less used by applications and I. stringify(value[, replacer[, space]]) Parameters value The value to convert to a JSON string.