Documentatie/Create-b-cropfield.md

## Creating a cropfield
This page explains what a cropfield is, and how to create one through the API.  

Agricultural datasets generally refer to a specif crop, at a specific location at a specific time. 
Therefore, we need to create a "Cropfield" item, to define this location and a timeframe our data relates to. 
A cropfield provides a convienient way to group all data for a crop grown on a specific plot during a season.
Farmmaps also uses the cropfield to collect and prepare context data such as weather, satelite imagery etc.

To create a cropfield we:
* Get the parent folder to place the cropfield under
* Create the cropfield

**Prerequisites**  
To create a cropfield we need:

* an acces token
* coordinates of the cropfield (what points define the plot contour)
* a startdate and an end date (what timeframe does this data aply to)

### Get parent element 
First, we'll get the parent code needed to place the cropfield in the hierarchy.
Usually this is a cropping scheme.
So when the code of the crop field is known, use this code as parent code to create the crop field and go to the next chapter.

## Get  cropping scheme
When the cropping scheme code is not known, we need to start from the top of the hierarchy, which is my_roots.

**Request**  
Replace `<acces token>` with your actual token.
```http
GET https://farmmaps.eu/api/v1/folders/my_roots HTTP/1.1
Host: farmmaps.eu
Accept: application/json
Authorization: Bearer <access token>
```

**Response**  
The response will be something similar to:

```http
HTTP/1.1 200 OK
Date: Fri, 27 Aug 2021 19:00:55 GMT
Content-Type: application/json; charset=utf-8
Connection: keep-alive
Server: Kestrel
Cache-Control: no-store,no-cache
Pragma: no-cache
Content-Length: 835

{
    "url":"/api/v1/folders/f25d8765a1cd407cb235961c73c268cf:USER_IN",
    "code":"f25d8765a1cd407cb235961c73c268cf:USER_IN",
    "name":"My Drive",
    "created":"2019-09-25T19:39:33.841835",
    "updated":"2019-09-25T19:39:33.841835",
    "itemType":"ROOT_FOLDER",
    "size":0,
    "state":0,
    "thumbnail":false
}
```

In the list returned, search for item which ends with USER_IN, which is shown above.
This item will be the parent of the cropping scheme.

So make another call to check if a cropping scheme exist.

**Request**  
Replace `<acces token>` with your actual token.
```http
GET https://farmmaps.eu/api/v1/items/f25d8765a1cd407cb235961c73c268cf:USER_IN/children HTTP/1.1
Host: farmmaps.eu
Accept: application/json
Authorization: Bearer <access token>
```

**Response**  
The response will be something similar to:

```http
HTTP/1.1 200 OK
Date: Fri, 27 Aug 2021 19:17:36 GMT
Content-Type: application/json; charset=utf-8
Connection: keep-alive
Server: Kestrel
Cache-Control: no-store,no-cache
Pragma: no-cache
Content-Length: 1519


{
		"parentCode": "f25d8765a1cd407cb235961c73c268cf:USER_IN",
		"geometry": {
			"type": "Point",
			"coordinates": [
				47.566119,
				7.605974
			]
		},
		"data": {},
		"tags": [],
		"isEditable": false,
		"url": "/api/v1/items/f3ee8e3ac55b43bc89757bcaedc89992",
		"code": "f3ee8e3ac55b43bc89757bcaedc89992",
		"name": "test scheme",
		"created": "2021-08-27T19:11:40.195449Z",
		"updated": "2021-08-27T19:11:40.195449Z",
		"dataDate": null,
		"dataEndDate": null,
		"itemType": "vnd.farmmaps.itemtype.croppingscheme",
		"sourceTask": null,
		"size": 0,
		"state": 0,
		"thumbnail": false
}
```

When the list is empty, you need to create a new cropping scheme, which is described in another thread.

The `parentcode` we need for creating a crop field is **"f3ee8e3ac55b43bc89757bcaedc89992"** 

### Create the cropfield
Now we can create the cropfield. We do so by setting `"itemType": "vnd.farmmaps.itemtype.cropfield"` and adding data to the geometry parameter.
Generally, a cropfield contour would be defined as a polygon, so we add `"type":"Polygon" and all the coordinates.  
We also need to specify a `dataDate` and a `dataEndDate` to indicate the the timeframe of the growing season.  
The `dataDate` needs to be before `dataEndDate` and cannot be on the same day.

**Request**

```http
POST /api/v1/items HTTP/1.1
Accept: application/json
Authorization: Bearer <acces token>
Content-Type: application/json
Cache-Control: no-cache
Host: farmmaps.awacc.nl
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Length: 916

{
    "parentCode": "6601a06d812b40f9830c9fe4e63b1944",
    "itemType": "vnd.farmmaps.itemtype.cropfield",
    "name": "cropfield test",
    "dataDate": "2021-1-18T00:00:0.0Z",
    "dataEndDate": "2021-12-18T00:00:00.0Z",
    "data": {},
    "geometry": {"type":"Polygon","coordinates":[[[6.09942873984307,53.070025028087],[6.09992507404607,53.0705617890585],[6.10036959220086,53.0710679529031],[6.10065149010421,53.0714062774307],[6.10087493644271,53.0716712354474],[6.10091082982487,53.0716936039203],[6.10165087441291,53.0712041549161],[6.10204994718318,53.0709349338005],[6.10263143118855,53.0705789370018],[6.10311578125011,53.0702657538294],[6.10331686552072,53.0701314102389],[6.103326530575,53.070119463569],[6.10309137950343,53.0699829669055],[6.10184241586523,53.0692902201371],[6.10168497998891,53.0691984306747],[6.10092987659869,53.0694894453514],[6.09942873984307,53.070025028087]]]}
}
```

**Response**
```http
HTTP/1.1 201 Created
Server: nginx/1.14.0 (Ubuntu)
Date: Fri, 27 Aug 2021 19:21:36 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: no-store,no-cache
Pragma: no-cache
Content-Encoding: br
Location: /api/v1/items/8ecbaa2d85d5484db7f16b281b7cd013
Vary: Accept-Encoding

{
    "parentCode":"6601a06d812b40f9830c9fe4e63b1944",
    "geometry": {
        "type":"Polygon",
        "coordinates":[[
          [6.09942873984307,53.070025028087],
          [6.09992507404607,53.0705617890585],
          [6.10036959220086,53.0710679529031],
          [6.10065149010421,53.0714062774307],
          [6.10087493644271,53.0716712354474],
          [6.10091082982487,53.0716936039203],
          [6.10165087441291,53.0712041549161],
          [6.10204994718318,53.0709349338005],
          [6.10263143118855,53.0705789370018],
          [6.10311578125011,53.0702657538294],
          [6.10331686552072,53.0701314102389],
          [6.103326530575,53.070119463569],
          [6.10309137950343,53.0699829669055],
          [6.10184241586523,53.0692902201371],
          [6.10168497998891,53.0691984306747],
          [6.10092987659869,53.0694894453514],
          [6.09942873984307,53.070025028087]]
        ]},
        "data":{},
        "tags":[],
        "isEditable":false,
        "url":"/api/v1/items/8ecbaa2d85d5484db7f16b281b7cd013",
        "code":"8ecbaa2d85d5484db7f16b281b7cd013",
        "name":"cropfield for VRA",
        "created":"2020-04-24T08:56:45.3727807Z",
        "updated":"2020-04-24T08:56:45.3727807Z",
        "dataDate":"2019-01-18T10:16:21.455Z",
        "itemType":"vnd.farmmaps.itemtype.cropfield",
        "size":0,
        "state":0,
        "thumbnail":false
      }
```

**Troubleshooting**
|Status code|Description|
|---|---|
|201|Cropfield created successfully|
|401|Error: not authenticated|
|403|Error: No write permissions in parent item|
|404|Error: Parent item not found|

Now that the cropfield has been created, we can start the processing by running a task.
This will collext all context data for the cropfield. 
We need the ItemCode of the cropfield to start the task so keep this at hand.