Large-scale acquisition method for street three-dimensional space model based on unit box

Abstract

The invention provides a street three-dimensional space model large-scale acquisition method based on a'unit box '. The method comprises the following steps: determining an acquisition area and acquiring basic data; identifying and screening effective street center lines, numbering and registering endpoint information; measuring and calculating the street average open space width of all effective streets based on a continuous equidistant sampling method; an expansion coefficient is set, and the widths of the three-dimensional space models of all the effective streets are calculated; corresponding unit boxes are constructed for all the effective street objects; and constructing a three-dimensional space model of all effective street objects by combining the unit box and the basic data, and performing associated marking on the three-dimensional space model and a corresponding street number. According to the method, a set of digital technical process is adopted, the building elements of the street interface are comprehensively considered, the street three-dimensional space model can be accurately measured and obtained on a large scale, and a more rational scientific basis is provided for urban design and planning and morphological research of streets.

Description

Technical Field

[0001] The invention relates to the field of urban design analysis, and in particular to a large-scale acquisition method of a street three-dimensional space model based on a "unit box". Background Art

[0002] Urban streets refer to urban streets within the city, with dense buildings on both sides, more commercial or social activities, high life and commercial attributes on both sides of the street interface, and sidewalks and municipal public facilities. As an important linear public space in the city, urban streets are an important component of urban texture and the basic framework of urban spatial organization. The collection of three-dimensional space of urban streets has important practical significance in the research of planning and other industries. In the field of urban design, the three-dimensional space research of streets is one of the preliminary work of design, which has an important impact on the designer's overall perception of the design scope, core concept generation, design plan deliberation, and later design expression. In the field of urban morphology research, it is also an important preparatory step to define and collect the three-dimensional space elements of the research. For relatively microscopic three-dimensional space elements such as urban streets, the degree of refinement of the collection will sometimes have a greater impact on the results of quantitative research.

[0003] However, the real three-dimensional spatial elements of streets are complex and subjective experience has a great influence on the definition and collection of urban streets, making it difficult to conduct precise analysis based on unified standards.

[0004] The most commonly used methods for defining and collecting the three-dimensional spatial model of urban streets are the division method based on the GIS framework and the division method based on the control detailed planning data. The former takes the street centerline as the center and uses a suitable distance as a buffer zone for the street centerline, thereby including the roads on both sides of the street centerline and the buildings on both sides of the street into the final street range; the latter is based on the control detailed planning data of the research scope, based on the land use information therein, and includes part of the land on both sides of the street centerline into the street range. Both can define the scope of the street to a certain extent, but both have some limitations. For the former, the scales of streets in different regions and types are different, and it is difficult to accurately define the ideal street range using one or several fixed buffer distances; for the latter, it is difficult for researchers to obtain detailed information, and not all regions have relevant control detailed plans, which makes it extremely difficult to collect streets on a large scale. At the same time, if there are too many land use types beside the street, the error of this method will also be uncontrollable. Summary of the invention

[0005] In order to solve the above technical problems, refine the definition and collect urban street space morphology models on a large scale, the present invention proposes a large-scale collection method of street three-dimensional space models based on "unit boxes".

[0006] The technical solution provided by the present invention is: a large-scale acquisition method of a three-dimensional street space model, the method comprising:

[0007] A large-scale acquisition method of a street three-dimensional space model based on a "unit box", characterized by comprising:

[0008] Step 1: Determine the collection scope and obtain basic data;

[0009] Step 2: Identify and select valid street center lines, number them and register their endpoint information;

[0010] Step 3: Measure and calculate the average street open space width W0 of all valid streets based on the continuous equidistant sampling method;

[0011] Step 4: Set the expansion coefficient k and calculate the street three-dimensional space model width W of all valid streets;

[0012] Step 5: Construct the corresponding "unit box" for all valid street objects;

[0013] Step 6: Combine the “unit box” with the basic data to construct a three-dimensional spatial model of all valid street objects, and associate and mark them with the corresponding street numbers.

[0014] As a preferred embodiment of the present invention, the basic data in step 1 includes layer information such as street centerline, building outline and building height in the acquisition area. Among them, the building outline and the street centerline must be at the same height, that is, the z-axis is at 0 elevation, and the building outline and the building height form a one-to-one correspondence, that is, one building outline object corresponds to one building height data information;

[0015] As a preferred embodiment of the present invention, the identification method in step 2 is: using the street centerline information to obtain all intersections in the layer, and calculating the length of the polyline of the street centerline between any two intersections, which is recorded as l i , and compare it with the given length parameter L. Usually, the value of the length parameter L is affected by the block size, etc., and is usually 30m, 50m, 100m, etc. i The street center lines with lengths ≥ L are considered valid street center lines, which are used to constrain the minimum length of the measured streets. The valid street center lines are numbered in sequence. For the street center line numbered i, any end point of the street center line is denoted as M. i , the coordinates are (a i1 ,b i1 ); let the other endpoint be N i , the coordinates are (a i2 ,b i2), the coordinates of all endpoints are arranged in descending order of ordinate and numbered with natural numbers;

[0016] As a preferred embodiment of the present invention, in step 3, the specific steps of continuously sampling the center line i of any valid street at equal intervals and calculating the average street open space width W0 of the valid street include:

[0017] 3-1 Determine the starting and ending points of the valid street centerline. The determination method is that the endpoint with a larger endpoint number is the starting point, and the endpoint with a smaller endpoint number is the end point.

[0018] 3-2 Set the sampling interval Δa. The sampling interval Δa is affected by the street scale, etc. It is usually an integer, such as 1m, 2m, 3m, 5m, 10m, etc., and must satisfy Δa<l i Starting from the starting point of the street centerline, equidistant sampling is performed along the street centerline according to the sampling interval to obtain several sampling points. When Δa·n≤l i And Δa·(n+1)>l i When , the sampling stops, and a total of n sampling points are obtained, which are O i1 ,O i2 ,O i3 ,……,O in .

[0019] 3-3 Set the maximum sampling buffer distance d. The maximum sampling buffer distance d is affected by the scale of the studied street, and is usually set to 50m, 100m, 200m, etc. Take each sampling point as the starting point, and draw the normal line l and l' of the street center line within the range of distance d on both sides of the street for all sampling points. The end point is the first intersection point of the normal line with the surrounding building outline. The length of the normal line is recorded as the effective normal line length. If there is no intersection point between the normal line and the surrounding building outline within the maximum sampling buffer distance d, the effective normal line length is recorded as 0. For sampling point O i1 , normal l i1 and l i1 The normal length of ′ is sampled with width denoted as x i1 and x i1 ′, and finally get all sampling widths x i1 ,x i2 ,x i3 ,……,x in ,x i1 ′,x i2 ′,x i3 ′……,x in ′;

[0020] 3-4 Calculate the average street open space width W0, the specific expression is:

[0021]

[0022] As a preferred embodiment of the present invention, in step 3, the sampling interval Δa and the length parameter L in step 2 must satisfy:

[0023] L≥m·Δa

[0024] Where m is a natural number not equal to 0, which is used to ensure that there are no less than m sampling points for any street;

[0025] As a preferred embodiment of the present invention, in step 4, the relationship between the street three-dimensional space model width W of the effective street and the street average open space width W0 of the effective street is:

[0026] W = k·W0;

[0027] As a preferred embodiment of the present invention, the expansion coefficient k in step 4 is usually about 2, indicating that the width of the three-dimensional street space model of the effective street is roughly about twice the average open space width of the street.

[0028] As a preferred embodiment of the present invention, in step 5, the "unit box" is a model carrier that represents the three-dimensional street space. The specific method of constructing the "unit box" for all valid street objects is:

[0029] 5-1 The street centerline of the effective street is used as a buffer zone with the width W of the street three-dimensional space model, so as to obtain the bottom area of ​​the "unit box". The shape of the bottom of the "unit box" is affected by the polyline corresponding to the street centerline. If the street centerline is a line segment, the bottom shape of the "unit box" is a rectangle; if the shape of the street centerline is a curve, the bottom shape of the "unit box" is not a rectangle;

[0030] 5-2 The height of the "unit box" is the maximum building height within the collection area, denoted as H. The "unit box" stretched out at this height can ensure that within the effective street range, all the final obtained street three-dimensional space models are within their respective "unit boxes";

[0031] As a preferred embodiment of the present invention, in step 6, the specific method of combining the "unit box" with the basic data to construct the three-dimensional space model of all valid street objects is: firstly, all the building outlines in the collection area are highly stretched to form an overall three-dimensional space model of the collection area, and then the overall three-dimensional space model is cut with the "unit box" corresponding to the valid street object to obtain the three-dimensional space model of the street, and it is associated with the corresponding street number. The specific cutting method is:

[0032] 1. The building model inside the "unit box" is completely preserved;

[0033] 2. The building model intersecting with the "unit box" is cut into two parts by the "unit box". The part inside the "unit box" is completely retained, and the part outside the "unit box" is not considered as part of the street;

[0034] 3. Building models located outside the "unit box" are not considered to be part of the street.

[0035] Compared with the prior art, the advantages of the present invention are as follows:

[0036] ① Wide adaptability: When faced with research areas with incomplete basic data, it is relatively easy to obtain basic data for operation, so that the three-dimensional spatial model of the research street can be quickly collected. It has a wide range of applications and low difficulty in collecting data on the research object.

[0037] ② Strong adaptability: It can flexibly respond to streets of different sizes and shapes, improve the degree of automation of the demarcation process, avoid errors caused by human judgment or lack of experience in traditional methods, and reduce the impact of human intervention and subjective judgment.

[0038] ③ High intelligence: Through the algorithm to automatically process the plan map information, it can accurately identify and define the reasonable street range on a large scale, ensure the uniformity of standards in the collection process of urban streets of different scales and types, and enhance the scientificity and rationality of urban street research. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a technical flow chart of a large-scale acquisition method of a street three-dimensional space model based on a "unit box" of the present invention;

[0040] Figure 2 is a schematic diagram of equidistant sampling according to the method of the present invention;

[0041] Figure 3 It is a schematic diagram of the sampling process from the effective sampling point to both sides of the street center line of the present invention;

[0042] Figure 4 It is a schematic diagram of a three-dimensional space model around a certain intersection established by using Sketchup software according to the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0044] Embodiment 1: A method for large-scale acquisition of a three-dimensional street space model based on a "unit box", the method comprising the following steps:

[0045] Step 1: Determine the collection scope and obtain basic data;

[0046] Step 2: Identify and select valid street center lines, number them and register their endpoint information;

[0047] Step 3: Measure and calculate the average street open space width W0 of all valid streets based on the continuous equidistant sampling method;

[0048] Step 4: Set the expansion coefficient k and calculate the street three-dimensional space model width W of all valid streets;

[0049] Step 5: Construct the corresponding "unit box" for all valid street objects;

[0050] Step 6: Combine the “unit box” with the basic data to construct a three-dimensional spatial model of all valid street objects, and associate and mark them with the corresponding street numbers.

[0051] The basic data in step 1 includes the street centerline, building outline, building height and other layer information in the acquisition area. The building outline and the street centerline must be at the same height, that is, the z-axis is at 0 elevation, and the building outline and the building height form a one-to-one correspondence, that is, one building outline object corresponds to one building height data information;

[0052] The identification method in step 2 is: using the street centerline information to obtain all the intersections in the layer, and calculating the length of the polyline of the street centerline between any two intersections, which is recorded as l i , and compare it with the given length parameter L. Usually, the value of the length parameter L is affected by the scale of the block, and is usually 30m, 50m, 100m, etc. i The street center lines with lengths ≥ L are considered valid street center lines, which are used to constrain the minimum length of the measured streets. The valid street center lines are numbered in sequence. For the street center line numbered i, any end point of the street center line is denoted as M. i , the coordinates are (a i1 ,b i1 ); let the other endpoint be N i , the coordinates are (a i2 ,b i2 ), the coordinates of all endpoints are arranged in descending order of ordinate and numbered with natural numbers;

[0053] Among them, in step 3, the specific steps of continuously sampling the center line i of any valid street at equal intervals and calculating the average open space width W0 of the valid street include:

[0054] 3-1: Determine the starting and ending points of the valid street centerline. The determination method is that the endpoint with a larger endpoint number is the starting point, and the endpoint with a smaller endpoint number is the end point.

[0055] 3-2: Set the sampling interval Δa. The sampling interval Δa is affected by the street scale, etc., and is usually an integer, such as 1m, 2m, 3m, 5m, 10m, etc., and must satisfy Δa<l i Starting from the starting point of the street centerline, equidistant sampling is performed along the street centerline according to the sampling interval to obtain several sampling points. When Δa·n≤l i And Δa·(n+1)>l i When , the sampling stops, and a total of n sampling points are obtained, which are O i1 ,O i2 ,O i3 ,……,O in .

[0056] 3-3 Set the maximum sampling buffer distance d. The maximum sampling buffer distance d is affected by the scale of the street being studied, and is usually set to 50m, 100m, 200m, etc. In this example, the maximum sampling buffer distance d is 100m. Take each sampling point as the starting point, and draw the normal line l and l' of the street center line for all sampling points within the range of distance d on both sides of the street. The end point is the first intersection of the normal line and the surrounding building outline. The length of the normal line is recorded as the effective normal line length. If there is no intersection between the normal line and the surrounding building outline within the maximum sampling buffer distance d, the effective normal line length is recorded as 0. For sampling point O i1 , normal l i1 and l i1 The normal length of ′ is sampled with width denoted as x i1 and x i1 ′, and finally get all sampling widths x i1 ,x i2 ,x i3 ,……,x in ,x i1 ′,x i2 ′,x i3 ′……,x in ′;

[0057] 3-4 Calculate the average street open space width W0, the specific expression is:

[0058]

[0059] In step 3, the sampling interval Δa and the length parameter L in step 2 must satisfy:

[0060] L≥m·Δa

[0061] Where m is a natural number not equal to 0, which is used to ensure that there are no less than m sampling points for any measured street. In this example, the sampling interval Δa is 5m;

[0062] Wherein, in step 4, the relationship between the street three-dimensional space model width W of the effective street and the street average open space width W0 of the effective street is:

[0063] W = k·W0;

[0064] The value of the expansion coefficient k in step 4 is usually around 2, which means that the width of the three-dimensional street space model of the effective street is roughly twice the average open space width of the street.

[0065] In step 5, the "unit box" is a carrier for representing the three-dimensional street space model. The specific method for constructing the "unit box" for all valid street objects is:

[0066] 5-1 The street centerline of the effective street is used as a buffer zone with the width W of the street three-dimensional space model to obtain the bottom area of ​​the "unit box". The shape of the "unit box" is affected by the polyline corresponding to the street centerline. If the street centerline is a line segment, the shape of the "unit box" is a rectangle; if the shape of the street centerline is a curve, the bottom shape of the "unit box" is not a rectangle;

[0067] 5-2 The height of the "unit box" is the maximum building height within the collection area, denoted as H. The "unit box" stretched out with this height can ensure that within the effective street range, all the final obtained street three-dimensional space models are within their respective "unit boxes";

[0068] Among them, in step 6, the specific method of combining the "unit box" with the basic data to construct the three-dimensional space model of all valid street objects is: first, all the building outlines in the collection area are highly stretched to form an overall three-dimensional space model of the collection area, and then the overall three-dimensional space model is cut with the "unit box" corresponding to the valid street object to obtain the overall three-dimensional space model of the street, and it is associated with the corresponding street number. The specific cutting method is:

[0069] 1. The building model inside the "unit box" is completely preserved;

[0070] 2. The building model intersecting with the "unit box" is cut into two parts by the "unit box". The part inside the "unit box" is completely retained, and the part outside the "unit box" is not considered as part of the street;

[0071] 3. Building models located outside the "unit box" are not considered to be part of the street.

[0072] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A large-scale acquisition method of a street three-dimensional space model based on "unit box", characterized in that: The method comprises the following steps: Step 1: Determine the collection scope and obtain basic data; Step 2: Identify and select valid street center lines, number them and register their endpoint information; Step 3: Measure and calculate the average street open space width W0 of all valid streets based on the continuous equidistant sampling method; Step 4: Set the expansion coefficient k and calculate the street three-dimensional space model width W of all valid streets; Step 5: Construct the corresponding "unit box" for all valid street objects; Step 6: Combine the "unit box" with the basic data to construct a three-dimensional spatial model of all valid street objects, and associate and mark them with the corresponding street numbers.

2. According to the method for large-scale acquisition of street stereoscopic spatial models based on "unit box" in claim 1, it is characterized in that: The basic data in step 1 includes layer information such as street center lines, building outlines and building heights in the collection area. Among them, the building outline and the street center line must belong to the same height, that is, the z-axis is at 0 elevation. At the same time, the building outline and the building height form a one-to-one correspondence, that is, one building outline object corresponds to one building height data information.

3. The large-scale acquisition method of street three-dimensional space model based on "unit box" according to claim 1 is characterized in that: The identification method in step 2 is: use the street centerline information to obtain all the intersections in the layer, and calculate the length of the polyline of the street centerline between any two intersections, which is recorded as l i , and compare it with the given length parameter L, and all the i The street center lines with lengths ≥ L are considered valid street center lines to constrain the minimum length of the measured street. The valid street center lines are numbered in sequence. For the street center line numbered i, any end point of the street center line is marked as M. i , the coordinates are (a i1 , b i1 ); let the other endpoint be N i , the coordinates are (a i2 , b i2 ), arrange the coordinates of all endpoints in descending order of vertical coordinates and number them with natural numbers.

4. The method for large-scale acquisition of street stereoscopic spatial models based on "unit box" according to claim 1 is characterized in that: In step 3, the specific steps of continuously sampling the center line i of any valid street at equal intervals and calculating the average street open space width W0 of the valid street include: 3-1 Determine the starting and ending points of the valid street centerline. The determination method is that the endpoint with a larger endpoint number is the starting point, and the endpoint with a smaller endpoint number is the end point. 3-2 Set the sampling interval Δa, start from the starting point of the street center line, and perform equidistant sampling along the street center line according to the sampling interval to obtain sampling point O i1 , O i2 , O i3 ,......,O in , a total of n, 3-3 Set the maximum sampling buffer distance d, take each sampling point as the starting point, and draw the normal line l and l' of the street center line within the range of distance d on both sides of the street for all sampling points. The end point is the first intersection point of the normal line with the surrounding building outline. The length of the normal line is recorded as the effective normal line length. If there is no intersection point between the normal line and the surrounding building outline within the maximum sampling buffer distance d, the effective normal line length is recorded as 0. For sampling point O i1 , normal l i1 and l i1 The normal length of ′ is sampled with width denoted as x i1 and x i1 ′, and finally get all sampling widths x i1 , x i2 , x i3 , ......., x in , x i1 ′,x i2 ′,x i3 ′......,x in ′; 3-4 Calculate the average street open space width W0, the specific expression is:

5. The large-scale acquisition method of street stereoscopic space model based on "unit box" according to claim 1 is characterized in that: In step 3, the sampling interval Δa and the length parameter L in step 2 must satisfy: L≥m·Δa Where m is a natural number not equal to 0, which is used to ensure that there are no less than m sampling points for any measured street.

6. The method for large-scale acquisition of street stereoscopic spatial models based on "unit box" according to claim 1 is characterized in that: In step 4, the relationship between the street three-dimensional space model width W of the effective street and the street average open space width W0 of the effective street is: W=k·W0.

7. The large-scale acquisition method of street stereoscopic space model based on "unit box" according to claim 1 is characterized in that: In step 5, the specific method of constructing "unit boxes" for all valid street objects is: 5-1 The horizontal width of the "unit box" is kept equal, and the width is the street three-dimensional space model width W of the effective street obtained in step 4. At the same time, the center position of the bottom edge is always kept at the intersection with the street center line. The vertical direction is linearly extended along the corresponding street center line, and the starting point and end point of the extension correspond to the starting point and end point of the street center line respectively, thereby obtaining the bottom surface of the "unit box"; 5-2 The height of the "unit box" is the maximum building height within the collection area, denoted by H.

8. The method for large-scale acquisition of street stereoscopic spatial models based on "unit box" according to claim 1 is characterized in that: In step 6, the specific method of combining the "unit box" with the basic data to construct the three-dimensional space model of all valid street objects is as follows: first, all the building outlines in the collection area are highly stretched to form an overall three-dimensional space model of the collection area, and then the overall three-dimensional space model is cut with the "unit box" corresponding to the valid street object to obtain the three-dimensional space model of the street, and it is associated with the corresponding street number.

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