Türkiye'de karayolu etüd ve proje çalışmalarında uygulanabilecek fotogrametrik değerlendirme modeli ve öneriler

Abstract

Bu çalışmada fotogrametrinin karayolu etüd ve proje çalışmaların daki rolü araştırılmıştır. Bu amaçla karayolu etüd ve proje ça lışmalarının ülkemizdeki uygulaması incelenmiştir. Analitik hava triyangülasyon yönteminin uygulanması durumunda en uygun nokta dağılımının, elde edilecek presizyonların ve birim proje maliyet lerinin ne olacağı araştırılmıştır. Ayrıca en kesit nokta belir lemesinde kullanılan yöntemler ve presizyonları incelenmiştir. Bu amaçla ; Birinci bölümde karayolu uygulamaları için fotogrametrinin işlevi kısaca açıklanmıştır. İkinci bölümde karayolu etüd ve proje çalışmalarının ülkemizdeki ve diğer ülkelerdeki uygulaması kısaca incelenmiştir. Üçüncü bölümde f otogrametrik nokta belirtiminde kullanılan yön temler açıklanmış, demet yöntemine göre hazırlanan ve bu çalışmada kullanılan bilgisayar programı izah edilmiştir. Bilgisayar prog ramı test alanlarında denenmiş, "Gramastetten" ve "Cumbrian"bloku nun değişik ölçmelerinin sonuçları bu çalışmada elde edilen sonuç larla kıyaslanmıştır. Sayısal uygulama olarak bir karayolu bloku nun ölçmeleri yapılmış ve demet yöntemine göre dengeleme sonunda elde edilen sonuçlar irdelenmiştir. Dördüncü bölümde en kesitlerde nokta belirleme yöntemleri kısaca açıklanmış ve sayısal uygulama olarak uygulama alanındaki en kesit noktalarının klasik fotogrâmetrik ve sayısal yükseklik modeli so nucu oluşturulan noktaların yükseklikleri hesaplanmış ve jeodezik yükseklikleri ile kıyaslanmıştır. Beşinci bölümde Türkiye'de halen karayolu etüd ve proje çalışmala rında kullanılan yöntemlere göre elde edilebilecek proje birim alan maliyetleri 1987 yılı birim fiyatlarına göre hesaplanmış ve yöntemlerin maliyete ilişkin kıyaslamaları yapılmıştır. Çalışma sonunda elde edilen sonuçlar ve öneriler sunulmuştur.

Photogrammetrical techniques are very helpful and very important tools in the collection and application of topografical informa tion necessary for highway design and project studies. But some differences are observed in different countries according to different application levels. The photogrammetry is being used for highway design and project studies in our country for selection of aligments, pre-project studies and preparation of application projects. The majority of photogrammetric work for this purpose is consist of firstly the determination of aligment from 1:10000 - 1:25000 scale maps or the determination of fly route from 1:15000 - 1:40 000 scale air photos and secondly gathering 1:2000 - 1:1000 scale maps for pre-projects studies. In this study, the role and function of photogrammetry in highway design and project studies are searched. For this purpo se, geodetic, analog and analitic photogrammetric methods have been scrutinized and necessary hardware, available precision and probable unit project cost have been evaluated. To this end, the application of higway design and project studi es undertaken in our country have been examined and in the case of application of aerial triangulation method, the results for the best point distribution, their precisions and unit project cost have been obtained. Morever, the methods used for the cross-section point determination and their precisions have be en presented. In the first sections, the function of photogrammetry for highway applications are shortly explained. In addition, the previous researchs in this field are briefly prensented. In the second section, the photogrammetric applications in our country and other countries are being briefly viewed. Currently the pool method for determination of photogrammetric points is being used in our country. '¦.«¦ V?f^ %J>& Û«'^ This method requires that at least 5 geodetic points are aVad.1- -t ¦ *r;**, i^f able in the proper locations for this reasons, for the applfeçâtjA^ -a: *'^ Vf»V ons in our country, for one kilometer aligment 7.6 controj;" "^..- ints are necessary in 1:1000 scale and 5.6 control points are necessary in 1:2000 scale has been observed. The calculations of this networks are' obtained with geodetic methods. Later the planimetric and height precisions obtained from this methods are evaluated. In geodetic methods, the planimetric and height precisions are defined as the tolerable maximum error. The precision ; in 1:2000 scale maps ±40 cm for planimetries, ±34.5 cm for heights. in 1:1000 scale maps ±20 cm for planimetries, ±17.2 cm for heights. are allowed. In photogrammetric method the planimetric and height precision are as follows. Point planimetric precision is given by the equation : m, = -v 3.mr.m hp px The height precision is determined by fly height or the precisi on of px paralax measurements. It is given by ; nL «» %o 0. lxh from fly height or by m. = (h/b)(h/p).m hp t px from px paralax measurements. In the third sections, the methods used for photogrammetric po int determination. For this purpose, the methods using strip, model and photos as unit are examined; their mathematical models briefly presented. vi *¦ 4K rf*... ^*v $ 5^,«f'^ V In addition the bundle method in photogrammetric aerial trian^ül?^."! lation, which has the best mathematical model, is explained iti - detail. Besides the mathematical model, the computer program prepared for the bundle method is introduced. The program is corrected so that it can be used for micro-computers which operates with DOS ( Disk Operating System). It can be used for the blocks which has a maximum of 25 photos, with a micro-computers which has 512 KB RAM ( Random Access Memory ) memory. This computer program was used for "Gramastetten" test field me asurements in Austrian and "Cumbrian-West" test field measure ment in Scotland and the results obtained from this test fields have been compared with the results obtained from the research and adjustment made in this subject. The adjustment of Gramastetten test field used 6 different pass point and Cumbrian West test field used 2 different pass points. In the Gramastetten test field, the block is consist of one strip with 10 photos and in the Cumbrian West test field three strips with 5 photos each strip (total 15 photos). The measurements of a highway block chosen as an application from our country have been conducted using an analog and anali- tic restitution instruments. For analitic measurements, Plani- comp C-115 (Carl Zeiss Oberkochen) stereo plotting instrument and for analog measurements, Topocart B (Carl Zeiss Jena) stereo plotting instrument. Stereo plotting instrument are used after the adjustments, it has been decided that the planimetric precision of analitic met hod 2.6 times better than that of analog method and height pre cision of analitic method 5.3 times better than that of analog methods. The precisions obtained with analitical measurement methods sa tisfy the tolerable error limits determined for our country con ditions. In the fourth sections, the point determination methods for cross-sections are searched. The photogrammetric methods used for this purpose are explained. The precisions and the capacity of this methods obtained in this methods are discussed. In conventional photogrammetric method, cross-sections points can be determined with height error of 10 cm. The researches conducted in this field show that this precision is sufficient for cross-sections point determination. In this method, some additional equipments must be connected to the stereo-plotting instrument. vii.; X* i The cross-section points can also be determined with digital heighting models. In this method, the surface of terrain is pre-' sented with least amount of sampling points, whose coordinates ' are measured with analog stereo plotting instruments. ".. The accuracy obtained using digital heighting model depends on the following conditions and variables. - the accuracy of measurement of sampling points, - the distrubition and density of sampling points, - whether the breat points / lines and morphological lines are included - the chosen interpolation method In order to show the attained precisions, in a numerical appli cation field, the heights obtained from digital height model / photogrammetric methods and the heights from geodetic methods are compared. As a result, it has been found that the heights obtained from conventional photogrammetric methods have a precision of ±15.9 cm, and those from digital height model of ±46.7 cm. In fifth section, the cost of highway design and project work using geodetic and photogrammetric methods in our country are calculated on the basis of 1987 unit prices. The American Dolar is used in this calculations. The costs in every methods are based on ; - production of design map, - project cost, - application and field work. The research shows that the geodetic method is the most expensi ve one (Table 5.10). The photogrammetric methods applied in Turkey results in %29.6 savement in 1:1000 scale map works, %41.4 savement. in 1:2000 scale map works. The savements for analictical methods are %56.8 in 1:1000 scale and %61.6 in 1:2000 scale map works. At the end, it has been decided that the photogrammetric method used with analitic aerial triangulation' is the cheapest of all other methods. viii /vs The followings are resulted from the research; ^ - In aerial triangulatlon, the precision obtained from bundle block c.Jjustment depends on the distribution of and amount of pass points. - the measurements of photos for bundle block triangu latlon must be conducted on comparator or analitical restitution instruments. - In the determination of cross-section points from di gital height models, besides the sampling points, the characteristic points presenting morphological lines and break lines must be included in the interpolation. It can be definetly said that the precision and cost obtained from analitic photogrammetric methods are very satisfactory for highway design and project work.