THE BORDER CITY AND ITS URBAN DEVELOPMENT: MARIBOR / OSIJEK / SUBOTICA

For the last couple of years I was involved in a co mparison research that has occupied me in various patterns. In 2011 a study of urban st ructure of more than fifty cities in central and eastern Europe with focus on former Yug oslav cities was conducted to specify the basic distinction of the ex – Yugoslav cities from similar central and east european cities. The research focused on the city s tructure and based on the available aerial photograph digital data cities of medium and large size (from approximately 100.000 to 2.000.000 inhabitants) were taken into c onsideration. A procedure to approach and trace the urban fabric was invented an d the urban structure was connected to the research of the city urban development histo ry and observation of entities and elements of specific urban structures in comparison to the urban development facts. According to the gathered data structural similarit es in former Yugoslav cities were recognized and defined, and a phenomena of “ex – yu goslav city” started to reveal itself.


The research method
For the last couple of years I was involved in a comparison research that has occupied me in various patterns. In 2011 a study of urban structure of more than fifty cities in central and eastern Europe with focus on former Yugoslav cities was conducted to specify the basic distinction of the ex -Yugoslav cities from similar central and east european cities. The research focused on the city structure and based on the available aerial photograph digital data cities of medium and large size (from approximately 100.000 to 2.000.000 inhabitants) were taken into consideration. A procedure to approach and trace the urban fabric was invented and the urban structure was connected to the research of the city urban development history and observation of entities and elements of specific urban structures in comparison to the urban development facts. According to the gathered data structural similarities in former Yugoslav cities were recognized and defined, and a phenomena of "ex -yugoslav city" started to reveal itself.
The spatial data and aerial / satellite photographs became publicly accessible for the region since 2009 and the structural studies can be conducted on data that corresponds to at least 1:5000 scale. The cities are covered in local aerial photographs and the region is covered in various satellite photographic materials.
For my doctoral dissertation a thorough study is in the phase of completion and it deals with the five chosen cities of the region, but the invented tracing procedure was used in various researches conducted in the last years 2 . The tracing method was used for the chosen cities of the dissertation, Sarajevo, Belgrade, Split, Maribor and Priština. The chosen cities were thoroughly studied in all their urban territory, i.e. throughout the urban fabric and suburbia, including the green system of the city borders, the surrounded rivers or sea. The procedure included three levels: -City view: a structural study of the relationship built / non built environment, -Urban structure view: a structural study of different city parts according to the readable and recognizable structural entities and -Detailed view: detailed reading of the urban fabric up to the urban block size. The tracing procedure was captured in screenshot digital photographs that are representing the basic findings, these were later used to compare the city attributes. The research continued in a second wave of detailed view studies that were based on more thorough observation and additional check-up of the recognized phenomena. Basically, the city development traceable periods show four distinctive city fabric shapes / periods that were defined by its main characteristics: the "core" period reveals the city founding principles; the "gründerzeit" city flourishing period of the Austro -Hungarian rule shows the stage of civil society expansion; the "socialist" period witnessed the power of the dictated development; and the "turbo -urban" period leaves us with what the postmodern and contemporary urban management principles (or the absence of them) have done to the city fabric.

The research frame
The tracing procedure was applied to the three border cities in order to possibly discover similarities of their "urban development character" in various development periods: along with Subotica, two other cities were chosen because of the same size and the position on the northern ex-Yugoslav border: Maribor and Osijek. At studying the city development a side effect was discovered: all of the cities have experienced similar situation after the WW2: due to the border settings they were mirrored by twin cities of great resemblance in only about 100 km distance: Subotica by Szeged, Hungary, Osijek by Pecs, Hungary and Maribor by Graz, Austria. The similarity continues in the fact that the "twin" northern cities are developed up to twice bigger in the post WW2 period. Although the setup for the comparison seemed plain and dull, the results of the trace procedure exceeded the expectations.

THE BORDER CITY AND THE URBAN DEVELOPMENT TRACES
A method of comparison the chosen cities seems to be appropriate, the urban structure of them was looked at, traced and the conclusions derived from the observations; the three chosen cities seem to be united in the "imperfection". Although today similar in size, their urban development is quite different; even more -perhaps the size is the only binding element of them. Approaching them, the looked at cities do not reveal its urban development easily, but in tracing parts of urban fabric the developments become more clear.

Osijek and its urban fabric development
The "core" period shows that the preserved basic unit is the old fortress Tvrdjava, neatly situated at the bending of the Drava river. The position in the actual 21 st century city is showing that the preserved core is the representative in urban image -the city core sits almost in the middle of it. The structural image of the city also shows that this core is still defining the city structure -not only the "gründerzeit" developments are respecting it, but also later structural decisions like the bridges position, the green system design and the main city traffic system. The core period in Osijek has its meaning and its influence throughout the whole development.
The "gründerzeit" city flourishing period of the Austro -Hungarian rule is the motor of the city structure in Osijek "downtown". A very distinct border of this city development is preserved and the block structure is maintained just as the core. 3 Although the city expansion is not the most powerful, the regulated order represents itself in still preserved urban blocks and very appropriate design of city streets. In this period Osijek shows the difference between center and the suburbs, the one is regulated with closed blocks with relatively clean green semi -private or common courtyards and the others with the clean regulated street line and facade and totally intimate individual backyards.

Photo 2. Osijek "core"and the "Gründerzeit" developments (Google Maps, ©2014 CNES / Astrium, Cnes / Spot image, Digital Globe)
The "socialist" period witnessed the power of the dictated development -in Osijek the developments of this period were obviously "greenfield" designs. Their undoubted quality is connected to the urban fabric; in Osijek the socialist city developments show a great understanding of connecting, filling the gaps or ending the city. This tradition is not often seen, especially not in larger city developments.
Osijek has examples of a decent, clean city border, and also neighbourhoods that are of sensible urban design and fit into the surrounding city fabric with more consideration than elsewhere in former Yugoslav cities. Apparently, the "turbo -urban" period in Osijek deals with some very contemporary issues in urban planning: be it conversions of the existing enclaves or designing the city southern borders, some structural order is continued and extended, there is hardly any massive irregularities in city structure and the city builds itself with public or semipublic interventions. Not turbo -urban at all.

Subotica and its urban fabric development
The "core" period of Subotica reveals the city urban design principles; Subotica in the urban development matter is a "Gründerzeit city". The core is really established and included in the urban structure in the city flourishing period of the Austro -Hungarian rule. Surprisingly, the principle of building closed blocks was not accepted and pursued in the city centre -the design principle is rather oriented to the street and open space -it gives the city centre an unique and vivid image. The similar principle of urban fabric can be understood at observing the pre WW2 city parts also -a great value is set to the street façade front appearance and it seems that the backyards have a totally closed intimate character.

Photo 3. Subotica city core; street and open space design rather than "classical" block structure (Google Maps, ©2014 Cnes / Spot image, Digital Globe)
Such an approach to the clear distinction of intimate and public had a very harsh time in the "socialist" city developments of Subotica. It can be read from the observation of just a few developments of the "brave new urbanism" that the "solitairs floating in the semi public greenery" was not the cup of tea in this city. Although consequently and neatly planned in the strictly defined areas, these developments are perhaps only a proof for someone in the central government that Subotica is not different from any other city of that socialist state. It seems that the "socialist urbanism" was never really accepted in Subotica, perhaps due to the strong small scale street urbanism that created beautifuly secret and intimate city parts hidden from the street views. The "turbo -urban" period is not very distinctive in Subotica -it is perhaps the majority of the city fabric is designed in an "user friendly" manner already -in most cases illegal or half legal city developments 4 are an anarchic answer to the "official" city developments. Looking for them, you can find "official" city developments in Suboticabut they are strongly outnumbered.

Maribor and its urban fabric development
The city "core" is medieval and very typical; like the cities of the southern german tradition the urban core is a walled city of relatively distinct quadratic structure. The interesting on the open space development are the contents of the city squares; their characters define the city extenstions of the "gründerzeit" period.
Photo 5. Maribor medieval core and the blocks of the "gründerzeit" period (Google Maps, ©2014 Cnes / Spot image, Digital Globe) The "gründerzeit" city period is moderate in Maribor -the city extensions to the northeast of the medieval core are regulated and consequently pursued. However, the post WW1 development went into other directions -regulations were smaller -scaled and insignificant due to diluted expansions. The "socialist" period witnessed two currents; the more interesting is the city renewal movement -as Maribor was heavily bombed the WW2 it was an essential approach to city development -the less felicitous the "Maribor Jug" expansion project, a 70ties "modernist neighbourhood experiment". It shows that Maribor has a tradition of "uncompleted projects" -all of the periods show a great deal of improvisation and some 70% of completion in average. The three "big developments", on southwest, southeast and east, are not very well bound into the city fabric. The "turbo -urban" period rises the standards, converts the city from industrial to a service city and converts many areas to new functionis, dilutes the industrial areas and keeps the city in its borders. The small scale developments are often in conflict with the surroundings, but the city keeps the green surrounding areas as a valued and preserved quality.

THE RELATIONSHIP BORDER CITY / NEIGHBOUR CITY
A significant moment in the city development is the competition. All of the considered cities of ex Yugoslavia have been always compared to their neigbours and this relationship is very specific.
Photo 6. Szeged, "gründerzeit" on the west bank, and "socialist" on the east bank (Google Maps, ©2014 Cnes / Spot image, Digital Globe) The three neighbouring cities, Graz, Pecs and Szeged are larger, more important and have some more urban structure qualities. Pecs has a very exclusive city core and consequent socialist urban developments, Szeged has a strict "gründerzeit" city form in the historic city and a vaste, almost perfectly arranged "socialist" developments on the southern Tisa side and to the east, Graz has a beautifuly preserved medieval city core and imaginative "gründerzeit" developments with a great tradition of the city living qualities, on top of it the architectural expressive school of the contemporary urban planning period.
Photo 7. Pecs, medieval city core (Google Maps, ©2014 Digital Globe) But there seems to be a charm in the mistakes, the specifics, the local imperfect flavours -neighbouring cities may have more power and more inhabitants and more development possibilities, but the readability of the city character is weak. The more regulated, the less characterised? This question needs to be researched yet.

CONCLUSION
The cities and its urban development can be studied and researched in a tracing procedure -the city fabric studied reveals not only how the structure is bound tohether, but also, which are the space and urban design qualities cherished throughout the history and the which are the beloved distinctive urban development periods of the city inhabitants. Apart from unfolding the illusion that the urban planners are the real builders of the city, the observation of the city structure is obligatory when trying to understand the priorities, the character and the flavour of every city, be it young or old.