Digital terrain models offer a representation of the relief south of the 52nd parallel, in the form of an elevation matrix. This matrix makes it possible to visualize the territory in perspective and to perform three-dimensional spatial analyses, using appropriate software. A module specialized in three-dimensional data processing, such as 3D Analyst or Spatial Analyst, is required to visualize the digital altitude model in three dimensions. This digital altitude model (10-meter pixel matrix) is obtained by processing altimeter data (level curves and elevation points) from ** [topographic databases on a scale of 1/20,000] (https://www.donneesquebec.ca/recherche/fr/dataset/cartes-topographiques-a-l-echelle-de-1-20-000) **.**This third party metadata element was translated using an automated translation tool (Amazon Translate).**

A digital terrain model (DTM) is a digital representation of elevations throughout the Province. DTM files contain elevation mass points, check points, spot heights and random densified points. The spacing between the elevation points is approximately 70 metres and the absolute vertical accuracy of a single elevation point is approximately 2.5 metres. The elevations are expressed as metres above mean sea level.

The digital terrain model (DTM) is a simplified representation of ground altimetry. The available data is in the form of an irregular triangular mesh (TIN). This is polygon numerical geographic data constructed by triangulating a set of points. The vertices are connected to a series of segments to form a mesh of triangles of different dimensions. This representation can be used as a basis for the 3D buildings of the digital base model. It should be noted that the data made available by the City is proposed for planning purposes and not for construction purposes given the associated decimeter details. The [3D buildings 2016 (LOD2 model with textures)]] (https://donnees.montreal.ca/ville-de-montreal/batiment-3d-2016-maquette-citygml-lod2-avec-textures2), the [2013 3D buildings (2013 3D buildings (CityGML LOD2 model with textures)] (/city-of-montreal/model-numeric-plateau-mont-royal-buildal-build2-buildings-lod2-with-textures), or the [3D buildings 2009 (CityGML LOD2 model with textures)] (/city-of-montreal/model-numeric-plateau-mont-royal-build2-buildings-lod2-with-textures), or the [3D buildings 2009 (CityGML LOD2 model with textures)] (/city-of-montreal/model-numerique-plateau-mont-royal-batiments-lod2-with-textures), or the [3D buildings 2009 (CityGML LOD2 model with textures)] (/city-of-montreal/model-numeric-s-citygml-lod2-with-textures) complement the digital terrain model in the urban territorial representation of Montreal. The [elevation data from aerial LiDAR] (/city-of-montreal/lidar-aerien-2015) are also available on the portal.**This third party metadata element was translated using an automated translation tool (Amazon Translate).**

### #Des hydrocoherent numerical terrain models (MNT-HC) are also offered south of the 52nd parallel. They are accessible via the [High Resolution Quebec Hydrographic Network Geobase (GRHQ-HR)] (https://www.donneesquebec.ca/recherche/dataset/geobase-du-reseau-hydrographique-du-quebec-a-haute-resolution-grhq-hr) These hydrocoherent numerical terrain models (DTM — HC) offer a regional numerical representation of Quebec relief based on altimetric (altitude) and planimetric (rectangular or geographic) data. They are the result of a collaboration between the Ministry of Natural Resources and Forests (MRNF) and Natural Resources Canada (NRCan) within the framework of the Agreement to produce an up-to-date digital map of northern Quebec and the creation of the product “National Hydro Network (RHN)” for the territory of Quebec. When integrated into a geographic information system, these models allow the implementation of multiple types of spatial analyses such as natural risks, landscape analysis, infrastructure implementation, etc. Hydrocoherent MNTs are obtained as a result of hypsometric and hydrographic data processing that uses the concept of hydrocoherence consisting in interpolating altimetric values by ensuring a connected drainage network and an accurate representation of ridges and watercourses. The oriented RHN filament makes it possible to grade lakes and to control the altimeter descent of watercourses. The final product is a quality portrait of relief on a scale of 1/50,000. DMTs provide altitude values that are based on a grid with a resolution of 0.324 arcseconds in geographic coordinates, which corresponds to a resolution of about 10 meters in the field.**This third party metadata element was translated using an automated translation tool (Amazon Translate).**

__The link: *Access the data directory* is available in the section*Dataset Description Sheets; Additional Information*__. Products derived from lidar (Light Detection and Ranging) are generated as part of the provincial lidar sensor data acquisition project. It is therefore to facilitate the use of raw lidar data and optimize its benefits that the Ministry of Natural Resources and Forests (MRNF) generated and made available products derived from lidar in a user-friendly format. Lidar technology makes it possible to accurately provide information such as ground altitude, forest cover height (canopy), slopes, and contour lines. Here is the list of the five derivatives: + Digital terrain model (spatial resolution: 1 m) + Digital terrain model in shaded relief (spatial resolution: 2 m) + Canopy height model (spatial resolution: 1 m) + Slopes (spatial resolution: 2 m) + Level curve (range: 1 m) This data covers almost all of the southern part of the province. This map is distributed by map sheets at a scale of ** 1:20,000**. ⚡ If you want to download **lidar point clouds**, please consult the Quebec Lidar Data page. __ ⚠️ 1) Note that__ the resolution of the following products (digital terrain model, digital terrain model in shaded relief, canopy height model and slopes) **has been slightly degraded** when viewed in the interactive map to ensure efficient display. __ ⚠️ 2) Note that__ **the planimetric and altimeter accuracy of the curves is variable**, but inevitably lower than that of the lidar surveys used to generate them. Moreover, it is recommended to use these level curves only for visual representations, and not for quantitative analyses. **This third party metadata element was translated using an automated translation tool (Amazon Translate).**

The joint Natural Resources Canada/Department of Fisheries and Oceans Marine Spatial Planning Program requires the highest resolution marine based bathymetric elevation data and adjacent land based topographic elevation data that are available. This digital elevation model of Canada's west coast compiles the best data available from multiple government agencies to create a regional model gridded at 10 meter spacing. The transitions between the marine and terrestrial areas are seamless creating a continuous surface of elevations for scientific research and mapping.

A lidar dataset (*light detection and ranging*) is a collection of 3D points represented in the form of a point cloud, generated from laser surveys (airborne). Remote sensing by airborne laser or lidar refers to a remote sensing or optical measurement technology based on the analysis of the properties of laser light returned to its emitter. The coordinates of the lidar points correspond to the precise positions where the laser pulses emitted by the lidar sensor have been reflected by objects or surfaces. In other words, each lidar spot represents a specific location where the light beam touched a surface and returned to the sensor. These coordinates are expressed in three dimensions (X, Y, Z) and make it possible to create very detailed and accurate representations of the terrain. In particular, lidar data allows: * to generate, among other things, numerical terrain (DTM) and surface (MNS) models; * to visualize the territory in perspective; * to perform three-dimensional spatial analyses for various needs, including: * the identification of areas potentially exposed to landslides and bank erosion; * landslide modeling; * the production of by-products and analyses of forest sectors; * the delimitation of flood zones. These datasets are the result of various intergovernmental collaborations, in particular with several ministries of the Government of Quebec, as well as with the federal government and the municipal sector. The geographic coverage corresponds to the information available on the download map and will be improved according to the availability of new data. In most cases, the data shown on this map corresponds to classified data. In the absence of classified data, but in the presence of raw data, it is the latter that will be presented on the map. Users of [*Open Forest*] (https://www.foretouverte.gouv.qc.ca/?pos=@-69.01196,50.56983&ctx=_telechargement&layers=236id,0v,38z;275id,272pid,1v,6z&groups=272id,T%C3%A9l%C3%A9chargement%20-%20Lidar%20(nuages%20de%20points)t,5z,1v,1e) can also download this data on this platform. **This third party metadata element was translated using an automated translation tool (Amazon Translate).**

High-resolution relief data produced from LiDAR surveys and limited to crop plots are particularly useful in the agricultural sector since they make it possible to model surface drainage in order to identify drainage problems or the risks of soil erosion. Agronomic interpretation will take advantage of this information not only in the form of the numerical terrain model and the shading, but also with the level curves, flow paths and basins located inside the cultivated plots, as delimited by the database of declared agricultural plots and productions (BDPPAD) of the Financière Agricole du Québec (FADQ). Level curves of 1 m covering the entire treated territory excluding cultivated plots (agricultural, forest, urban, etc.) are also available. These new data are the result of a collaboration between the MRNF and the MAPAQ, and they are offered thanks to the open valorization of data initially derived from LiDAR to the MRNF Forest Inventory Directorate (DIF). We hope that this data will support better soil and water management interventions, in order to mitigate the consequences of climate change, and to promote sustainable agriculture.**This third party metadata element was translated using an automated translation tool (Amazon Translate).**