METHOD FOR PREPARING A REPRESENTATION OF A GEOGRAPHICAL POLYGON

Abstract

A computer-implemented method including receiving a first representation of a geographical polygon defining a parcel of land, which first representation includes latitude and longitude coordinates that represent at least the corners of the geographical polygon; based on the first representation, determining various features of the geographical polygon; and preparing a second representation of the geographical polygon, which second representation includes the geometric centre of geographical polygon, first two alphanumeric characters, second two alphanumeric characters, a fifth alphanumeric character, and a sixth alphanumeric character.

Claims

1. A computer-implemented method, comprising: receiving a first representation of a geographical polygon defining a parcel of land as shown on a digital satellite and/or aerial image, the first representation including latitude and longitude coordinates (Lat1-4; Long1-4) that represent at least corners of the geographical polygon; based on the first representation, determining a geometric centre of the geographical polygon, determining half a length of the geographical polygon in a north-south direction and providing first two alphanumeric characters (XX) representing the determined half-length of the geographical polygon in the north-south direction, determining half a width of the geographical polygon in an east-west direction and providing second two alphanumeric characters (YY) representing the determined half-width of the geographical polygon in the east-west direction, determining which shape of a preselected number of different shapes that best matches the geographical polygon and retrieving from a table a fifth alphanumeric character (Z) representing that shape, and determining a principal axis of the geographical polygon and providing a sixth alphanumeric character (A) representing an angle (θ) of the determined principal axis relative to the north-south direction; and preparing a second representation of the geographical polygon, which second representation includes the geometric centre of the geographical polygon, the first two alphanumeric characters, the second two alphanumeric characters, the fifth alphanumeric character, and the sixth alphanumeric character.

2. The computer-implemented method according to claim 1, wherein determining the geometric centre of the geographical polygon includes determining a latitude coordinate (LatC) and a longitude coordinate (LongC) representing the geometric centre of the geographical polygon, and wherein the latitude coordinate and the longitude coordinate are included in the second representation of the geographical polygon.

3. The computer-implemented method according to claim 1, which method further comprises rotating the geographical polygon so that the determined principal axis aligns with the north-south direction.

4. The computer-implemented method according to claim 3, wherein said half the length and half the width are determined of the geographical polygon so rotated.

5. The computer-implemented method according to claim 1, wherein the first two alphanumeric characters (XX) representing the determined half-length of the geographical polygon in the north-south direction are provided by dividing the determined half-length by a pixel size of said digital satellite and/or aerial image, and wherein the second two alphanumeric characters (YY) representing the determined half-width of the geographical polygon in the east-west direction are provided by dividing the determined half-width by the pixel size of said digital satellite and/or aerial image.

6. The computer-implemented method according to claim 3, wherein determining which shape of a preselected number of different shapes that best matches the geographical polygon includes overlaying the different shapes over the rotated geographical polygon to determine which of the different shapes that overlays the rotated geographical polygon in a most accurate way.

7. The computer-implemented method according to claim 1, wherein the first two alphanumeric characters, the second two alphanumeric characters, the fifth alphanumeric character, and the sixth alphanumeric character are numerical digits.

8. The computer-implemented method according to claim 1, wherein the first two alphanumeric characters and the second two alphanumeric characters are letters.

9. The computer-implemented method according to claim 1, which method further comprises transmitting said second representation of the geographical polygon to an electronic device.

10. The computer-implemented method according to claim 1, which method further comprises displaying said second representation of the geographical polygon on a display.

11. The computer-implemented method according to claim 1, performed by an app on a smart phone or tablet.

12. A computer-implemented method, comprising: receiving a second representation of the geographical polygon, which second representation is prepared by the computer-implemented method according to claim 1; restoring the geographical polygon based on the second representation; and displaying the restored geographical polygon overlaid on the digital satellite and/or aerial image.

13. A computer program product comprising computer program code to perform, when executed on a computer, the method according to claim 1.

14. A non-transitory computer-readable storage medium comprising the computer program product according to claim 13.

15. An electrical signal embodied on a carrier wave and propagated on an electrical medium, the electrical signal comprising the computer program product according to claim 13.

16. A computer device, configured to perform the method according to claim 1.

17. The computer device of claim 16 being a smart phone or a tablet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing a currently preferred embodiment of the invention.

[0038] FIG. 1 schematically illustrates i.a. a computer device according to an aspect of the present invention.

[0039] FIG. 2 is a flow chart of a method according to aspects of the invention.

[0040] FIGS. 3a-g illustrate various steps of the present method.

DETAILED DESCRIPTION

[0041] FIG. 1 illustrates a computer device 100 according to an aspect of the present invention. The computer device 100 is here a smartphone (e.g. an iPhone or an Android phone). Alternatively, the computer device 100 could be a tablet (e.g. an iPad) or a laptop or a desktop computer.

[0042] The computer device 100 comprises an electronic display 102. The electronic display 102 may have a touchscreen, so that it except for showing information can serve as a user input device. The computer device 100 may also comprise a processor 104, a memory 106, and a storage 108. The computer device 100 may also comprise a GPS receiver 110 and wireless communication means 112.

[0043] Moving on, the computer device 100 may be configured to perform various specific steps or actions detailed in the following by means of an app 114 (computer program product). The app 114 may be downloaded to the computer device 100 and stored on the aforementioned storage 108. The app 114 may run or be executed on the mobile computing device 10 using the aforementioned processor 104 and memory 106.

[0044] Turning to FIG. 2, FIG. 2 is a flow chart of a method according to the first aspect (left) and the second aspect (right) of the present invention.

[0045] At S1, the method according to the first aspect comprises receiving a first representation 10 of a geographical polygon 12 defining a parcel of land 14, as shown on a digital satellite and/or aerial image 16, see FIG. 3a. The parcel of land 14 may for example be an agricultural farm, but could alternatively be real-estate, forest, a park, etc. The digital satellite and/or aerial image 16 may for example be a Sentinel satellite image. The first representation 10 includes latitude and longitude coordinates Lat1-4, Long1-4 that represent the corners (vertices) 18a-d of the geographical polygon 12. Here, the geographical polygon 12 is a (tilted) rectangle, but it could have any polygonal shape.

[0046] The first representation 10 of the geographical polygon 12 could be provided by (manually) marking the corners 18a-d of the parcel of land 14 as shown on the digital satellite and/or aerial image 16 of an electronic mapping service, at S0. For example, a user could mark the corners 18a-d as the digital satellite and/or aerial image 16 is displayed on the aforementioned electronic display 102 of the computer device (smartphone) 100, using a pointing device like their finger or a stylus pen.

[0047] At S2, the method determines the geometric centre (centroid) 20 of the geographical polygon 12, see FIG. 3b. The geometric centre 20 of the geographical polygon 12 may for example be determined using geometric decomposition, a technique which is known per se. The geometric centre 20 is preferably represented by a latitude coordinate LatC and a longitude coordinate LongC, for example 57.7065 and 11.9687.

[0048] At S3, the method determines a principal axis 22 of the geographical polygon 12, see FIG. 3c. The principal axis 22 is the axis for which the product of inertia is zero. The orientation of the principal axis 22 with respect to the centroidal coordinates LongC and LatC can be obtained using

[00001]${\theta }_p=\frac{1}{2}{\tan }^{-1}\left[\frac{2I_{\mathrm{LongCLatC}}}{I_{\mathrm{LatC}}-I_{\mathrm{LongC}}}\right]$

[0049] where I.sub.LongC, I.sub.LatC, and I.sub.LongCLatC represent the moments of inertia about the east-west direction 30, moment of inertia about the north-south direction 24, and the product of inertia with respect to east-west direction 30 and north-south direction 24, respectively. The angle θ.sub.p is measured positive counter clockwise from the centroidal east-west direction 30. From the angle θ.sub.p, the angle θ with the north-south direction 24 may be derived.

[0050] The method at S3 further provides a (sixth) alphanumeric character A representing the angle θ of the determined principal axis 22 relative to the north-south direction 24. The alphanumeric character A may for example be a digit 0-9, wherein A=0 represents 0 degrees and A=9 represents 324 degrees. The alphanumeric character A may for example be derived using the formula A=(angle θ made with vertical axis 24 clockwise)/36. Here, the angle θ is about 20 deg, whereby A=1.

[0051] At S4, the method may comprise rotating the geographical polygon 12 so that the determined principal axis 22 aligns with the north-south direction 24, see FIG. 3d.

[0052] At S5, the method comprises determining half the length 26 of the rotated geographical polygon 12 in the north-south direction 24, see FIG. 3e, wherein half the length is ½ the length of the principal axis 22 that intersects rotated geographical polygon 12 at both ends. The method at S5 further provides (first) two alphanumeric characters XX representing the determined half-length 26. The two alphanumeric characters XX may be provided by dividing the determined half-length 26 by the pixel size of the digital satellite and/or aerial image 16. For an exemplary half-length 26 of 500 m given a pixel size of 30 m, the two alphanumeric characters XX, in case they are digits 0-9, become 500/30=17 (rounded to the nearest integer).

[0053] At S6, the method comprises determining half the width 28 of the rotated geographical polygon 12 in the east-west direction 30, see FIG. 3f, wherein half the width is ½ the length of an axis, which axis passes through the geometric centre 20 and is perpendicular to the principal axis 22, that intersects rotated geographical polygon 12 at both ends. The method at S6 further provides (second) two alphanumeric characters YY representing the determined half-width 28. The two alphanumeric characters YY may be provided by dividing the determined half-width 28 by the pixel size of the digital satellite and/or aerial image 16. For an exemplary half-width 26 of 700 m given a pixel size of 30 m, the two alphanumeric characters YY, in case they are digits 0-9, become 700/30=23 (rounded to the nearest integer).

[0054] At S7, the method determines which shape of a preselected number of different shapes that best matches the (rotated) geographical polygon 12, and retrieves from a table a (fifth) alphanumeric character Z representing that shape. The table may for example be:

TABLE-US-00001 Z Shape 0 Circle 1 Rectangle 2 Rhombus 3 Triangle 4 Ellipse 5 Square 6 Trapezoid 7 Reserved 8 Reserved 9 Reserved

[0055] Specifically, determining which shape of that best matches the geographical polygon 12 may include overlaying the different shapes of the table, which overlaid shapes are adjusted based on the determined half-length 26 and half-width 28, over the rotated geographical polygon 12 to determine which of the different shapes that overlays the rotated geographical polygon 12 in the most accurate way. Namely, each overlaid and adjusted shape is rotated about the centroid, and for each rotation, the area not intersecting between the shape and the polygon 12 is estimated. The method thus derives areas not intersected for all rotation possibilities and shapes of the table. Given seven shapes as in the table above, and 36 different rotation angels, it results in 252 possibilities. Then, the shape with the least area lost during intersection is selected. Here, the most representative shape is a rectangle 32 (see FIG. 3g), which yields Z=1.

[0056] At S8, the method prepares a second representation of the geographical polygon, which second representation includes the geometric centre of geographical polygon (here LatC, LongC), the first two alphanumeric characters XX, the second two alphanumeric characters YY, the fifth alphanumeric character Z, and the sixth alphanumeric character A. Hence, the second representation may be (LatC, LongC) [XX YY ZA], for example (57.7065, 11.9687) [17 23 1 1].

[0057] At S9, the method may comprise transmitting the second representation 34 of the geographical polygon 12 to an electronic device 200, see FIG. 1. The second representation may for example be transmitted in an SMS message using the wireless communication means 112 of the computer device 100. The receiving electronic device 200 may be a feature phone.

[0058] Alternatively or complementary, the second representation may be displayed on the electronic display 102 of the computer device 100 (S10).

[0059] At S11, the method according to the second aspect of the invention comprises receiving the second representation 34 of the geographical polygon 12, by the computer device 100 or by another similar computer device 100′ running the same app 114, see FIG. 1. The second representation 34 (e.g. (57.7065, 11.9687) [17 23 1 1]) may for example be manually entered into the computer device 100′.

[0060] At S12, the method further comprises restoring the geographical polygon 12 based on the second representation 34, by performing steps S2-S8 “in reverse”. That is, the method may derive the shape defined by Z, adjust the half-length and half-width according to XX and YY, respectively, rotate the shape based on A, and the position the shape based on LatC and LongC.

[0061] At S13, the method displays the restored geographical polygon 12′ overlaid on a digital satellite and/or aerial image on the electronic display 102 of the computer device 100′, see FIG. 1. Hence, the parcel of land 14 can easily be identified on the digital satellite and/or aerial image.

[0062] In an exemplary use case of the present invention, a farmer can come to an agency or bank hosting the computer device 100 and—possibly with the help of a specialist—identify their parcel of land 14 on the digital satellite and/or aerial image 16, which allows for the provision of first representation 10. The computer device 100 then prepares the second representation 34 based on the first representation 10, and SMSs the second representation 34 to the farmer's feature phone. The farmer may then go to another agency or bank bringing the feature phone with him and present the second representation 34 to the another agency or bank, which then performs reconstruction using another computer device 100′, allowing the parcel of land 14 to be displayed and identified digital satellite and/or aerial imagery, which in turn for example can be used to analyze the credit worthiness of the farmer. It is expected that the present invention can be of great use for farmers especially in the developing world.

[0063] The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.