OBIS: Edit Geodata

Revision as of 12:21, 21 February 2013

For the import of geodata you will be automatically redirected to the JanusWeb. Click "New Import" in the menu on the left side and the following screen appears. If you cannot access this site please make sure that you are logged in and that you have required rights for the import of data.

Import of shape data or images

For data import you have to select the format of the geodata with the help of the pull down menu. The formats ESRI Shape file, TIFF and GeoTIFF, CSV and Dbf (dBase format) can be imported. The import process cannot be executed if you try to upload an unidentified format. You have two possibilities to upload data:

• You need to give the path to each single file. E.g. if you want to import a shape file you need to select the shape file (shp), dbase file (dbf), index file (shx) and optionally the projection file (prj). Because of safety measures filling fields automatically is not allowed.
• Tick the box if you want to upload data from the archive. The archive alreday contains all associated data. The following archives are supported:
  • Zip archives with the extension .zip
  • Tape archives with the extension .rar
  • Compressed tape archives with the extension .tgz or .tar.gz

Enter the path of the archive or of the single shape files in the corresponding entry fields. The button "search" opens a helpful browser. Then click on the button "import".

The data were sent to JanusWeb and listed after transferred successfully.

For a correct illustration or conversion of the vector data information about the projection need to be given in Spatial Reference Identifier (SRID) form. For shape files such a SRID is either generated automatically from a provided projection file (.prj) - if this file is provided- or needs to be selected from a list. You get a detailed description of the selected SRID when you click on "information". You can enter the projection ID in the menu "determining SRID" with the help of the pull down menu.

The next step is to import data into an import table. This temporal table contains the geometries and attributes of the shape file. On the next page you will get informed about the steps carried out and corresponding results. For bigger datasets it may take a time until the results are shown as the output will be generated after data have been imported. In a next step you need to decide either if you want to create a new table, overwrtite an existing table or attach data to an existing table. If you want to create a new table select the first item of the pull down menu and enter the name of the table into the entry field. In case that a table with this name already exists, an error message appears. If you select an already existing table, another pull down menu opens. In this menu you can determine whether data shall be attached to the table or shall be substituted. If you overwrite an existing table, the existing table from the database and the entry from the PostGIS management table will be deleted. Afterwards the procedure is the same as for a new table. In case you want to add data to an existing table two new columns were added to the existing attributes. The attribute "gid" is a new artificial primary key, which is used to identify objects within the system. The attribute "the_geom" contains the geometry of the object. For a correct application both columns need to be taken over as a geometric table.

Next to the attribute columns, geometric data as the column "the_geom" and an object_ID are added. In the entry field "where statement" you can determine a statement, which must be set up in the SQL-syntax without a leading WHERE-key word. Consequently, the import is restricted to the data that fullfill this condition. If all information are given, the following steps can be accomplished:

• • creating a new table
  • copying data from the import table to the target table
  • updating PostGIS information
  • entering authorizations for the target table
  • setting up a spatial index for the target table

Afterwards you have to click the subitem "view data" of the menu item "edit data".

A table with available vector data appears. In the pull down menu on the top of the table you can also switch to other data types, e.g. raster data. The first columns gives metadata information such like title of dataset, type and ESPG code. Vector data were distinguished according POINT, LINESTRING or POLYGON geometries. Additionally, all of these versions are available with the prefix MULTI. In the second column you get a preview of the shapefile. In the third column you find four features: "preview" displays a preview of the shapefile in a new window, "download" to export data, "generate new map from this data" and "add data as layer to an existing map".

Download data

Generate a new map

You can generate a new map by clicking on the respective button. Here you can give a title to the map, define the projection and select layers. Further you can define the extent, size, status on or off, transparency and units. You also have to set a cachetime.

You need to enter the EPSG number and save the settings. The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this data registry.

Add data as layer to an existing map

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