Kohalike geodeetiliste võrkude hooldamisest ja kasutamisest Tartu linna näitel
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Kuupäev
2021
Kättesaadav alates
10.09.2021
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Tagamaks mõõtmist ühtses geodeetilises süsteemis, on Eesti suuremates linnades ja asulates
pärast taasiseseisvumist rekonstrueeritud kohalikud geodeetilised võrgud. Kuigi praeguseks
on nende tähtsus tänu kiirele ja kättessaadavale võrgu RTK meetodile vähenenud, pole
kohalike võrkude hooldamisest Eestis loobutud. Üsna sageli jäävad kohaliku võrgu märgid
ette ehitus- ja arendustöödele ja vajaldavad teisaldamist, mille käigus tuleb uutele märkidele
nõuetekohase täpsusega koordinaadid mõõta ja arvutada.
Minu magistritöö eesmärgid on 1) kindlaks teha, missugune on efektiivseim viis üksikutele
kohaliku võrgu punktidele koordinaatide määramiseks ja 2) välja selgitada, kas kohaliku
geoarhiivi andmete abil on võimalik saada ülevaadet sellest, kui palju kohalikku geodeetilist
võrku üldse kasutatakse ja teha pilootuuring sel teemal.
Võrdlesin kolme kohaliku geodeetilise võrgu punkti näitel erinevate mõõtemeetodite
(polügonomeetria, staatiline GNSS mõõdistus, võrgu RTK ja joonelis-nurgalise vastulõige,
mille juures kasutatakse võrgu RTK meetodil mõõdetud ajutisi kindelpunkte) abil saavutatud
täpsusi ja kulunud aega. Kõige täpsem meetod on polügonomeetria, mis garanteerib ka võrgu
sisemise sidususe säilimise. Staatiline GNSS mõõdistus võimaldab aga kohalike võrke siduda
kaasaegse ja hästi hooldatud aktiivse referentsraamistikuga ja seetõttu arvan, et seda võiks
senisest enam kasutada. Võrgu RTK-l baseeruvad meetodid antud uurimuse kohaselt võrgu
üksikute punktide mõõtmiseks ei sobi.
Tartu linna Geoarhiivi andmete analüüsimisel selgus, et traditsiooniliste
maamõõtetehnoogiate kasutamisest on paljuski loobutud ja kohalik geodeetiline võrk leiab
üsna vähest kasutust. Selle taustal ja võttes arvesse, et võrgud vajavad umbes paarikümne
aasta järel täielikku rekonstrueerimist, tuleks kohalike võrkude tuleviku osas lähiaastail teha
strateegilisi otsuseid. Kohalike geodeetiliste võrkude kasutamine väärib edaspidi laiemat uurimist (kaasates teisi
asulaid, vaadeldes pikemat perioodi ja täpsustades valimi moodustamise metoodikat). Oma
töös keskendusin plaanilistele koordinaatidele, kuid kindlasti tuleks vaadata ka kohalike
kõrgusvõrkude kasutamist ja seda eriti nendes asulates, kus kõrgusvõrk on hiljuti
rekonstrueeritud.
In order to ensure measurement in a unified geodetic system, local geodetic networks have been reconstructed in larger urban settlements of Estonia since regaining independence in 1991. Although their importance has decreased due to the fast and easily available network RTK method, the maintenance of local networks has not ceased in Estonia. Development and construction activities in the cities often bring about a need to relocate geodetic control points, during which the coordinates of new points have to be measured and calculated with the required accuracy. The objectives of my master's thesis are 1) to learn the most efficient way to determine the coordinates of individual points of the local network, and 2) to find out whether the local geo archive data can provide an overview of the use of local geodetic networks and if so, conduct a pilot study on the subject. In the practical part of the work, I compared the accuracies achieved and time spent using different measurement methods (polygonometry, static GNSS measurement, network RTK, and resection combined with network RTK) in case of three local geodetic network points. The most accurate method is polygonometry, which also guarantees that the internal coherence of the network is maintained. However, static GNSS surveying allows local networks to be linked to a modern and well-maintained active reference framework, and I therefore think that it is justified to use the method more than it has been up to the present time. Study revealed that network RTK-based methods are not suitable for measuring individual points in a local geodetic network. The analysis of the data of the Geoarchive of the City of Tartu revealed that land surveying practices have changed in a way that traditional control point networks are used rather rarely. Against this background, and given that the networks need to be completely reconstructed every two decades, strategic decisions of how to continue with local networks are in order in the coming years. The use of local geodetic networks deserves further research (involving other cities and towns, looking at a longer period and specifying the sampling methodology). In my work, I focused on planar coordinates, but the use of local height control networks should definitely be studied more thoroughly, especially in those settlements where the height network has been recently reconstructed.
In order to ensure measurement in a unified geodetic system, local geodetic networks have been reconstructed in larger urban settlements of Estonia since regaining independence in 1991. Although their importance has decreased due to the fast and easily available network RTK method, the maintenance of local networks has not ceased in Estonia. Development and construction activities in the cities often bring about a need to relocate geodetic control points, during which the coordinates of new points have to be measured and calculated with the required accuracy. The objectives of my master's thesis are 1) to learn the most efficient way to determine the coordinates of individual points of the local network, and 2) to find out whether the local geo archive data can provide an overview of the use of local geodetic networks and if so, conduct a pilot study on the subject. In the practical part of the work, I compared the accuracies achieved and time spent using different measurement methods (polygonometry, static GNSS measurement, network RTK, and resection combined with network RTK) in case of three local geodetic network points. The most accurate method is polygonometry, which also guarantees that the internal coherence of the network is maintained. However, static GNSS surveying allows local networks to be linked to a modern and well-maintained active reference framework, and I therefore think that it is justified to use the method more than it has been up to the present time. Study revealed that network RTK-based methods are not suitable for measuring individual points in a local geodetic network. The analysis of the data of the Geoarchive of the City of Tartu revealed that land surveying practices have changed in a way that traditional control point networks are used rather rarely. Against this background, and given that the networks need to be completely reconstructed every two decades, strategic decisions of how to continue with local networks are in order in the coming years. The use of local geodetic networks deserves further research (involving other cities and towns, looking at a longer period and specifying the sampling methodology). In my work, I focused on planar coordinates, but the use of local height control networks should definitely be studied more thoroughly, especially in those settlements where the height network has been recently reconstructed.
Kirjeldus
Magistritöö
Geodeesia, kinnisvara- ja maakorralduse õppekaval
Märksõnad
magistritööd, kohalik geodeetiline võrk, passiivne referentsraamistik, geodeetiliste märkide teisaldamine