The CSDI Portal is the entry point of the CSDI where you can discover, view and use the spatial datasets for supporting your smart applications. The major functions of the Portal including search of dataset, showing content, download and preview. Please see the paragraphs below for more information about the functions:

• Searching of Spatial Dataset
• Information about a Spatial Dataset
• Format of Spatial Dataset available
• Geospatial and Data Query Services
• Preview a Spatial Dataset

Searching of Spatial Dataset

There are several ways for searching a spatial dataset:

• 1. By Keyword: Go to the Landing Page or click CSDI logo on the top left hand corner, input the keyword in the searching box on top part of the Page;
• 2. By Framework Spatial Data Themes (FSDT) and Data Categories: On the lower part of the Landing Page, you can select select a Theme from any of the 7 FSDTs or a category from any of the 18 dataset categories;
• 3. View All Datasets: Click Menu on the top left corner All Datasets.

Your searching result will be shown in the Catalog Page. Dataset title and basic description about the datasets will be displayed.

The searching result can be filtered by providing further keywords in the searching box of Catalog Page.

Information about a Spatial Dataset

In the Catalog Page, more information of a dataset can be shown by clicking the Dataset Title. The following information of the dataset extracting from the metadata will be displayed:

• General description and technical information (e.g. Data Specification, Spatial Datum, Metadata Standard, etc.);
• Data update frequency;
• Contact information of data contributor.

Apart from the above information, you can download the spatial data by clicking Download Dataset next to the Abstract Section or connecting the web service resources from your system via the copied resource link by clicking the Web Service Link above the Other Resources Section.

Format of Spatial Dataset available

To provide more flexibility for CSDI Portal users in utilizing the available spatial data, the Portal aims to convert the source format into different open machine-readable data formats and commonly used data formats, including GML, GeoPackage, KML, GeoJSON, File Geodatabase(FGDB), Shapefile(SHP) and CSV. While the conversion module of the Portal was well tested, it is possible to have minor inconsistency due to the large variety of geometric elements, data schemas and projection representations between the common spatial data formats available.

Besides, due to the technical limitations of different data formats (e.g. supporting geometry type, field value limitation, etc.), fewer choices of data formats may be provided for some vector datasets. Users are suggested to explore and download other available data formats for supporting your applications.

For image/raster datasets, GeoTiff data format will be the only format available in the Portal.

Geospatial and Data Query Services

To support existing API users of Hong Kong GeoData Store and new users who wish to develop new/smart applications, there are various API services provided on the CSDI Portals that allow users to access the corresponding datasets:

First, the Portal provides Web Feature Service (WFS) and Web Map Service (WMS) under open international standards to support developers for obtaining spatial data in vector or raster natures. Developers can understand more about the functions of these GeoSpatial Services (e.g. data query and filtering, image control, etc.) by visiting GeoSpatial Services.

Second, for developers looking for a simple approach to extract spatial data from the Portal, Data Query Service offers an HTTP-based API for developers to retrieve the relevant data. By clicking the “Data Query Service” button on dataset Metadata Page, developers can utilize the available querying functions on an interactive user interface to customize for a query URL, preview the query result and extract the spatial data in JSON format. For certain datasets which the Portal cannot provide the Data Query Service due to data complexity or other technical limitations, developers are recommended to use the GeoSpatial Services (i.e. WFS and WMS) of those datasets for their applications.

Preview a Spatial Dataset

There are several ways to preview a spatial dataset:

• 1. In Catalog Page, click Preview in Map below the dataset title and next to the Abstract Section to preview it on the Map View Page;
• 2. In Metadata Page showing dataset details, click Preview in Map under Download Dataset to preview the spatial dataset.

The Map View Page currently supports display of over 400 datasets. Click Layer List on Map Tools Menu to control the display and style of the previewing datasets.

For the basic map layer, you can click BaseMap on Map Tools Menu of Map View Page to select either colour, greyscale or orthophoto imagery as background when previewing your dataset.