# Downloading, Replacing, Appending Data

## Downloading

If you have the permissions to do that, from the layer detail page it will be possible to download it in several output format. The conversion will be performed automatically by GeoNode through the `OGC Protocols`.

- Move to the `Mainrd` layer

    `http://localhost/layers/geonode_data:geonode:Mainrd`
    
- Click on the `Download Layer` button; it will show up a small window with several options and choices

    ![image](https://user-images.githubusercontent.com/1278021/136572879-6dc826b5-5aba-4086-a97b-024d3dbebf7e.png)

- The first tab, `Images`, is not tipically much useful. It does not allow you to download any kind of _raw data_, but just some _portryals_ in several image format, which could be used eventually as thumbnails if needed. You can try out by clicking on some of the available image formats.

- The second tab, `Data`, allow you to download the whole layer or a subset of it in some different download format.

### Downloading the whole layer

From the `Data` section it is possible to download the _raw data_ into several `output formats`.

![image](https://user-images.githubusercontent.com/1278021/136574918-1114da80-4b0f-4b43-9354-50cbd44bd822.png)

 - The `Original Layer` link, will allow you to retrieve the original files used to create the layer the first time. This link might be unavailable in some cases:
     - The layer has been created from the backend, i.e. it has not been uploaded from the `Upload Panel`
     - The original files are not available anymore on the file system
     - The administrator removed the link

 - Moreover the `Original Layer` link differs from the others for two main things:
     1. It will always ignore any kind of filter appliead to the `Download Form` and it will provide the whole files.
     2. It may refer to some external repository in the case the administrator has changed it. In that case it will redirect the download of the files to some external storagre.

 - Other `download formats`; those ones are available accordingly to:
     1. The type of layer; it is possible that some layers could not be converted on some specific layer (e.g. vectorial and rasters)
     2. Plugins availablity on `GeoServer`; the conversion in this case will be done by the backend on-the-fly. The available outputs, therefore, depend on their availability on the geospatial service.

### Obtaining a filtered subset

This option is valid only for `VECTORIAL` layers.

- From the `Data` section it is possible to create and apply some filtering in order to get only a subset of the whole layer.
- Click and enable the `Do you want to filter it?` button from the `Download` tab. It will take some time to parse the values from the backend.

    ![image](https://user-images.githubusercontent.com/1278021/136577215-072477e5-7e7b-4fdb-991e-9792a94e45bd.png)

- First of all select the type of logic operator, `All == AND`, `Any == OR`

    ![image](https://user-images.githubusercontent.com/1278021/136762112-83c74297-a892-4836-ad9c-1d7632b75e4d.png)

- Next, select the attribute you want to use to filter the subset

    ![image](https://user-images.githubusercontent.com/1278021/136762307-289abb7f-91eb-41cd-be63-74ee638912a2.png)

- Select the logic operator to match the value, e.g. `LIKE` means `contains`

    ![image](https://user-images.githubusercontent.com/1278021/136762906-cb0cbf8b-0043-4e7b-b14c-6405e5d49eb4.png)

- Select from the values list or enter a custom one

    ![image](https://user-images.githubusercontent.com/1278021/136763098-2c63a383-48aa-4ae5-aeec-00015c350be8.png)

- Click on the `+` button in order to add the condition to the filter; notice how the selected condition will be listed below

    ![image](https://user-images.githubusercontent.com/1278021/136763239-7fb9b54a-3f19-4621-9198-2ba2ac388677.png)

- Through the `Feature Limit` it is possible to further limit the number of the records returned

    ![image](https://user-images.githubusercontent.com/1278021/136763363-952ce9e3-63ab-4390-a154-6aba98351c9b.png)

- The following one is an example of `OR` filter on the `LABEL_NAME` attribute using a `LIKE` operator in order to match more results; the outcome is then limited to the first `100` records

    ![image](https://user-images.githubusercontent.com/1278021/136763601-1c549042-70ab-4253-b91a-d400d9856a82.png)

- Finally select the `Output Format` you want the results to; e.g. by selecting `GeoJSON` you will get the following results form the above example

    ```json
    {
      "type": "FeatureCollection",
      "features": [
        {
          "type": "Feature",
          "id": "Mainrd.59",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3062088.181,
                  1249165.789
                ],
                [
                  3062451.08,
                  1249272.489
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 59,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.61",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061723.714,
                  1249069.253
                ],
                [
                  3062088.181,
                  1249165.789
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 61,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.86",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061355.12,
                  1248969.761
                ],
                [
                  3061723.714,
                  1249069.253
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 86,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.88",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3062451.08,
                  1249272.489
                ],
                [
                  3062824.349,
                  1249369.35
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 88,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.140",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3059898.114,
                  1248600.093
                ],
                [
                  3059912.48,
                  1248594.44
                ],
                [
                  3059941.91,
                  1248593.56
                ],
                [
                  3060145.13,
                  1248645.4
                ],
                [
                  3060250.16,
                  1248676.419
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 140,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.229",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3060987.191,
                  1248873.845
                ],
                [
                  3061355.12,
                  1248969.761
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 229,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.255",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3060619.651,
                  1248775.923
                ],
                [
                  3060987.191,
                  1248873.845
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 255,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.321",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3060250.16,
                  1248676.419
                ],
                [
                  3060619.651,
                  1248775.923
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 321,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.527",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3063555.141,
                  1249566.88
                ],
                [
                  3063930.22,
                  1249668.529
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 527,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.579",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3064612.55,
                  1249853.859
                ],
                [
                  3064809.989,
                  1249906.62
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 579,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.632",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061252.3,
                  1249341.19
                ],
                [
                  3061201.959,
                  1249524.828
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 632,
            "LABEL_NAME": "11th St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.633",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3065453.729,
                  1250103.404
                ],
                [
                  3065760.373,
                  1250187.36
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 633,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.704",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3064294.881,
                  1249767.116
                ],
                [
                  3064317.058,
                  1249773.172
                ],
                [
                  3064612.55,
                  1249853.859
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 704,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.720",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3063192.21,
                  1249469.411
                ],
                [
                  3063555.141,
                  1249566.88
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 720,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.779",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3066127.684,
                  1250290.216
                ],
                [
                  3066254.58,
                  1250325.75
                ],
                [
                  3066333.921,
                  1250344.23
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 779,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.811",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061355.12,
                  1248969.761
                ],
                [
                  3061303.024,
                  1249159.043
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 811,
            "LABEL_NAME": "11th St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.841",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3065397.156,
                  1250087.79
                ],
                [
                  3065453.729,
                  1250103.404
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 841,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.879",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3063930.22,
                  1249668.529
                ],
                [
                  3064294.881,
                  1249767.116
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 879,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.988",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3064809.989,
                  1249906.62
                ],
                [
                  3064945.19,
                  1249942.75
                ],
                [
                  3065017.521,
                  1249974.065
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 988,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.1223",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3062824.349,
                  1249369.35
                ],
                [
                  3063192.21,
                  1249469.411
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 1223,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.1237",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061303.024,
                  1249159.043
                ],
                [
                  3061252.3,
                  1249341.19
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 1237,
            "LABEL_NAME": "11th St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.1368",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3065017.521,
                  1249974.065
                ],
                [
                  3065032.087,
                  1249979.471
                ],
                [
                  3065111.59,
                  1250008.98
                ],
                [
                  3065397.156,
                  1250087.79
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 1368,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.1383",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3065760.373,
                  1250187.36
                ],
                [
                  3066127.684,
                  1250290.216
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 1383,
            "LABEL_NAME": "Walnut St"
          }
        },
        {
          "type": "Feature",
          "id": "Mainrd.1461",
          "geometry": {
            "type": "MultiLineString",
            "coordinates": [
              [
                [
                  3061201.959,
                  1249524.828
                ],
                [
                  3061156.17,
                  1249707.58
                ]
              ]
            ]
          },
          "geometry_name": "the_geom",
          "properties": {
            "fid": 1461,
            "LABEL_NAME": "11th St"
          }
        }
      ],
      "totalFeatures": 24,
      "numberMatched": 24,
      "numberReturned": 24,
      "timeStamp": "2021-10-11T09:07:21.487Z",
      "crs": {
        "type": "name",
        "properties": {
          "name": "urn:ogc:def:crs:EPSG::2876"
        }
      }
    }
    ```

## Replace and Append Data

In order to execute this exercise let's use some specifi sample layer that will allow us to better visualize the outputs.

- From `/opt/data/sample_data/append_data_samples/distritos` upload the `distritos.shp` Shapefile

    ![image](https://user-images.githubusercontent.com/1278021/136764615-b79acefe-4056-469d-886e-88604678f231.png)

- Go to the `distritos` layer detail page and click on `Editing Tools > Layer > Edit Data`

    ![image](https://user-images.githubusercontent.com/1278021/136769237-439c0af7-c213-4fd8-8adc-efb85cd84ce2.png)

- Add a new polygon as shown in the figure below

    ![image](https://user-images.githubusercontent.com/1278021/136770612-8637c73b-9b64-47bb-9188-929a8392758b.png)

- Delete some features as shown in the figure below

    ![image](https://user-images.githubusercontent.com/1278021/136770755-d3fef80a-9f74-4315-bc29-1cc840cc6e1d.png)

- Go back to the layer details page; **remeber to clear the image cache of the browser everytime you perform an edit operation**

    ![image](https://user-images.githubusercontent.com/1278021/136770946-c64e1012-57a4-4288-b73d-10d3a281818f.png)

- Go to the `Editing Tools > Layer > Append Data`

    ![image](https://user-images.githubusercontent.com/1278021/136771104-3bb5a179-c914-4665-8ec8-7b54188d2061.png)

- Select the `distritos` shapefiles again and append them to the layer

    ![image](https://user-images.githubusercontent.com/1278021/136771953-7abf3017-a932-46d5-9909-14ebae3aacca.png)

- Go back to the layer details page, clear the image cache of the browser and refresh the page; notice that the operation restored the old deleted features by preserving the new ones

    ![image](https://user-images.githubusercontent.com/1278021/136772132-0acfb4a3-b53d-41af-8806-2f0afe0b19c7.png)

- Repeat the same this time by using the `Replace Layer` operation

    ![image](https://user-images.githubusercontent.com/1278021/136772212-505318fc-785c-4370-a79d-24af9a81586c.png)

    ![image](https://user-images.githubusercontent.com/1278021/136772271-2a58578f-1948-4c0e-8f63-0a5e35ba7378.png)

- Go back to the layer details page, clear the image cache of the browser and refresh the page; notice now that the layer features have been restored to the original ones

    ![image](https://user-images.githubusercontent.com/1278021/136772365-4592f4d3-0eca-4090-aafc-225983dc6f78.png)

#### [Next Section: Accessing Data from External Clients (QGIS)](CONNECT_QGIS.md)