<p>Stone walls in agricultural land are incorporated in the general protection of biotopes. They are protected because they provide a habitat for endangered species. Therefore it is illegal to carry out proceedings in an area that is included in the protection of biotopes. In order to do that, exemption is needed which can only be granted if there are special reasons. The essay stipulates what these special reasons are.</p><p>In an exemption errand the interest for nature conservation must be weighed against a public or a private interest. Administrators have varying opinions on how the interest for nature conservation, contra individual and public interests shall be evaluated. The interest for nature conservation has a lower value if the wall lacks endangered species or if stone walls are common in the area. But a lower value, in itself, can never be considered as special reasons.</p><p>When it comes to a public interest, it must be an important one in order to bring about an exemption. Examples of important public interests are animal and health protection.</p><p>Private interests are often constituted by the desire to improve the farming profitability. This is however rarely considered as an “unforeseen situation”, and therefore - according to preparatory work - it is not judged as special reasons.</p><p>One conclusion is that the County Administrative Boards need improved guidance. Another conclusion is that exemption shall be used restrictively. Exemptions are not supposed to solve all problems due to protection of stone walls in agricultural land. They ought to be the solution when no other reasonable alternatives can be found.</p>

Stone walls in agricultural land are incorporated in the general protection of biotopes. They are protected because they provide a habitat for endangered species. Therefore it is illegal to carry out proceedings in an area that is included in the protection of biotopes. In order to do that, exemption is needed which can only be granted if there are special reasons. The essay stipulates what these special reasons are. In an exemption errand the interest for nature conservation must be weighed against a public or a private interest. Administrators have varying opinions on how the interest for nature conservation, contra individual and public interests shall be evaluated. The interest for nature conservation has a lower value if the wall lacks endangered species or if stone walls are common in the area. But a lower value, in itself, can never be considered as special reasons. When it comes to a public interest, it must be an important one in order to bring about an exemption. Examples of important public interests are animal and health protection. Private interests are often constituted by the desire to improve the farming profitability. This is however rarely considered as an “unforeseen situation”, and therefore - according to preparatory work - it is not judged as special reasons. One conclusion is that the County Administrative Boards need improved guidance. Another conclusion is that exemption shall be used restrictively. Exemptions are not supposed to solve all problems due to protection of stone walls in agricultural land. They ought to be the solution when no other reasonable alternatives can be found.

Detta arbete redogör för hur användning av den nya nationella höjdmodellen (NNH) ur/i Lantmäteriet databas kan användas i olika terräng och vilka förutsättningar det finns för identifiering av specifika landskapselement i denna, manuellt och visuellt. Sedan 2009 har Lantmäteriet laserskannat hela landet, både på land och över vatten. Uppdraget är slutfört 2015. Målet med laserskanning är att framställa en rikstäckande höjdmodell med ett medelfel som är bättre än 0.5 m. Idag är all NNH-data tillgänglig som LAS-filer på Lantmäteriets databas. För att kunna utföra ett utvärderingsexperiment valdes ett geografiskt begränsat område: I Skepplanda, Ale kommun i Västra Götalands län. De hjälpmedel som användes var GPS-mottagare, LAS-filer, Ortofoto och applikationsprogram såsom OL-laser och ArcGis. Det främsta syftet med studien var att undersöka hur bearbetning och utvärdering av olika kartmaterial kan utföras, för att sedan kunna bedöma i vilken mån användning av Lantmäteriets NNH-data, i olika typer av terräng, kan vara möjlig t.ex. hur små detaljer kan urskiljas i det. För undersökningen valdes specifika objekt, såsom stenmurar och ett dike. Tre olika kartunderlag framtogs av OL-laserprogrammet: lutningsbilder, intensitetsbilder och terrängskuggningsbilder. Utifrån insamling av inmätta punkter och med hjälp av vektordata kunde materialet utvärderas visuellt. Två kartor valdes, vilka uppfyllde kriterierna för att kunna uppnå studiens syfte. Eftersom kartan med terrängskuggning och lutningsbild ger en tydligare profil av områdets karaktäristiska drag på marknivå, är det möjligt att identifiera små markdetaljer såsom stenmurar och diken. Resultatet varierade från fall till fall, beroende på kartunderlaget. En mur på den ena platsen i en bild kunde t.ex. detekteras, men inte i en annan bild, trots att det finns en mur där. Studien visade att laserpulserna har svårt att tränga igenom tät vegetation, dock kan olika solvinklar och belysningsriktningar ändå framhäva vissa små markdetaljer under en tätskog. Andra faktorer som kan ha påverkat kvalitén på lasermaterialet är flyghöjden, laserskannerns vinkel och under vilken period under året skanningen genomfördes. Ett antagande gjordes, att laserskanning från lägre flyghöjd och mindre öppningsvinkel kan höja kvalitén på laserdata. Med dessa två faktorer kan högre upplösning per kvadratmeter yta uppnås. Ett annat sätt som kan vara aktuellt i en undersökning är att använda OL-laser verktygslåda och tillämpa andra inställningar genom att skapa objekthöjdbilder där höjd färgläggs med olika ekvidansnivå. Genom att prova fram olika inställningar i programmet, där olika lutningshöjd och solvinklar tillämpas kan läsbarheten på kartunderlaget förbättras. / This work describes how the use of the new national elevation model (NNH) from the National Land Survey database may be used in a variety of terrain and the conditions they are identification of specific landscape elements, manually and visually. From the start of 2009, the national land Survey laserscannat whole country, both on land and over water. The mission will be completed in 2015. The goal of laser scanning is to produce a nationwide elevation model with a standard error of better than 0.5 m for a 2 m GRID. Today, all NNH data available as LAS files on Lantmäteriet's database. To perform an evaluation experiment was elected a geographically limited area: Skepplanda, Ale Municipality in Västra Götaland. The devices used were GPS receiver, LAS files, Orth imagery and application programs such as OL laser and ArcGIS. The main aim of the study was to investigate the processing and evaluation of different map material can be performed, and then to assess to what extent the use of Lantmäteriets NNH- data in different types of terrain may be possible. For the investigation, the specific items, such as stone walls and a ditch. Three different maps material was developed by the OL laser program: slope images, intensity images and terrain shading images. Based on the collection of measured points and using vector data could material evaluated visually. Two maps were chosen, which met the criteria for being able to achieve the objectives of the study. Since the map with terrain shading and gradient image provides a clearer profile of the area's characteristic features at ground level, it is possible to identify small land features such as stone walls and ditches. Results will vary from case to case, depending on the substrate maps. A wall at one location in an image could e.g. detect, but not in another image, even though it's a wall there. That’s why definitive conclusions could be not established. The study showed that the laser pulses are difficult to penetrate dense vegetation; however different solar angles and lighting directions nonetheless highlight some small land details during a dense forest. Other factor that may have affected the quality of the laser material is the altitude, laser scans angle and during which period of the year the scan was performed. An assumption was made that the laser scans from lower altitude and smaller opening angle can add value to laser data. With these two factors, higher resolution per square meter of surface is achieved. Another way that can be relevant in an investigation is to use the OL laser toolbox and apply different settings to create objects height pictures where height is colored with different evidence level. By trying out different settings in the program, where different slope height and solar angles applied to the readability of the chart surface is improved.