Geodetic Hiking Portal
Jurica Jagetić, Drago Špoljarić | University of Zagreb, Faculty of Geodesy, Croatia
Keywords: Web GIS, Hiking portal, geodesy, trigonometrical points (pillars)
There are 75 trigonometrical points (pillars) of the 1st order on the territory of the Republic of Croatia. They are a part of a network that spans the country and is the basis of the national coordinate reference frame. Average distance between the points is approximately 30 km. Some of the pillars were built during the surveys by the Austro-Hungarian empire of the Croatian territory, while some were built during the Yugoslav surveys. During the surveys by the Republic of Croatia, many of the pillars were rebuilt and some eccentric position were set up. Since 1985 astro-geodetical measurements were performed on some of the points and since 1994 GNSS and geodynamic measurements.
Most of the trig points are on the summits of hills and mountains, some are in lowlands, and some are in towns and settlements, in which they are mostly church towers. As they are mostly on the summits, they are of great interest for hikers.
Geodetic Hiking Tour is a suggested tour to attract visitors to the trigonometrical pillars. A hiking tour consists of checkpoints connected in a meaningful manner. The mountaineering association responsible for the tour awards the visitors that fulfill certain criteria. The hiking tour can be a single trail, a network of trails or a collection of unconnected checkpoints on mountains, or a hiking competition without particular checkpoints but with some other criteria. The visit of a checkpoint is confirmed by stamping into a personal hiking journal or by a photo of the visitor at the checkpoint. Visitor that proves the fulfilment of the criteria of a trail is awarded by the organiser of the trail with a pin or a written acknowledgement (URL1).
Spatial data and attributes of the trigonometric points are collected for the realisation of the Geodetic Hiking Tour. They are then connected to a database with both geodetic and hiking information. Some of the data are obtained by searching the archives of former surveys, some is collected in the field, while some is collected by searching through the data of the Croatian Mountaineering Association and hiking maps.
The collected data are joined in the Geodetic Hiking Portal (URL2). It serves as the database and equips the user with useful tools for the preparation of hikes to the checkpoints. Alongside the Portal, an e-Log is developed. It is used to record the passing of the Geodetic Hiking Trail checkpoints (URL3).
With the development of the database with the spatial data and attributes of the trigonometrical points, geodesy in Croatia gets a new source of information about the basis of the coordinate reference frame. The historical and contemporary data point to the historical value of the trigonometrical pillars. The development of the portal further promotes the State Geodetic Administration, geodesy and the history of geodesy. It educates the hikers, cyclists and other travellers. The principal and the most beautiful Croatian Hiking Trail consists of 152 checkpoints and only 26 of them are summits with trigonometrical pillars. Hence, out of 75 trigonometrical points of the first order, 49 of them are unknown to the general public.
Jagetić J., 2017: Modeliranje baze, vizualizacija i analiza prostornih podataka Geodetske planinarske obilaznice (GPO), Master thesis, Geodetski fakultet Sveučilišta u Zagrebu, Zagreb
URL1: Planinarske obilaznice, http://www.hps.hr/info/planinarske-obilaznice/, 20.02.2018.
URL2: Geodetski planinarski portal, https://geopp.planinarski-portal.org/, 20.02.2018.
URL3: E-dnevnik Geodetske planinarske obilaznice, https://gpo-dnevnik.planinarski-portal.org/, 20.02.2018.